Transition from src:postgresql-9.5 to src:postgresql-9.6

This includes also some "no-change-rebuilds for 9.6".
They are in update excuses depending on postgres - please let us know if we shall create a list of those.

Jbicha will add some details but it seems we try to make it pass and then remove 9.5 from zesty.

Super-raw overview of remaining regressions:
- postgresql-plproxy
- posgresql-multicorn
- posgresql-filedump

I understand if you don't want to commit to maintaining 9.6 for zesty, but my first impression was that there was confusion about how close this transition was to being complete.

Will 18.04 LTS use 9.6 or 10 (10 is expected in 3rd Quarter 2017 according to https://www.postgresql.org/developer/roadmap/ ) ? Especially if 18.04 LTS uses 9.6 then it seems the maintenance burden might not be too bad since Debian Stretch is shipping 9.6 too and most of these packages are synced with Debian.

postgresql-plproxy's autopkgtest failures are not new (they failed in yakkety with 9.5 too) but I don't know about the other two autopkgtest regressions.

postgresql-filedump 9.6.0-1build1 passes tests.

postgresql-plproxy 2.7-1ubuntu1 passes tests locally. Submitted delta to Debian.

http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=856423 is the Debian report for the plproxy fix.

Thanks to Jeremy's digging, postgresql-multicorn has been failing for years in both Debian and Ubuntu. We just need to update the excuses hints at https://bazaar.launchpad.net/~ubuntu-release/britney/hints-ubuntu/view/head:/pitti#L164

plproxy does pass the tests now, but newpid fails to install under LXD. We can either mark this as ignoreable if it's a LXD bug or we can add a machine-isolation restriction if it's something fundamental. Verifying this on IRC and will update.

16:39 < stgraber> nacc: it's attempting to set fs capabilities, that's not
                  supported inside user namespaces by the kernel
16:40 < stgraber> nacc: most other packages fallback to setuid when that
                  happens (ping for example)
16:40 < stgraber> we also have a kernel fix for this but it's not been merged
                  mainline yet
16:42 < stgraber> hallyn wrote the patch and has been trying to get it merged
                  upstream for a while now

Based upon stgraber's input, switching the test dep to util-linux & unshare.

http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=856437

This bug was fixed in the package postgresql-plproxy - 2.7-1ubuntu2

---------------
postgresql-plproxy (2.7-1ubuntu2) zesty; urgency=medium

  * d/t/control: the newpid package fails to install in LXD
    environments (relies on fs capabilities which are disallowed by the
    kernel in user namespaces), so use unshare instead (LP: #1666566).

 -- Nishanth Aravamudan <email address hidden> Tue, 28 Feb 2017 16:28:57 -0800

src:postgresql-9.6 has transitioned, so now it's just removal of src:postgresql-9.5.

$ rmadison search -S postgresql-9.5 -s zesty | awk '{ print $1; }' | xargs -n1 reverse-depends | grep '^\*' | awk '{ print $2 }' | sort | uniq | xargs -n1 chdist bin2src zesty-proposed |sort | uniq
barman
postgresql-9.5
repmgr
$ rmadison search -S postgresql-9.5 -s zesty | awk '{ print $1; }' | xargs -n1 reverse-depends -b | grep '^\*' | awk '{ print $2 }' | sort | uniq | xargs -n1 chdist bin2src zesty-proposed |sort | uniq

barman recommends:

Recommends: openssh-server, openssh-client, postgresql-client | postgresql-client-9.6 | postgresql-client-9.5 | postgresql-client-9.4 | postgresql-client-9.3 | postgresql-client-9.2

So it is fine to leave as-is

repmgr (3.3.2):

Depends: postgresql-9.6-repmgr | postgresql-9.5-repmgr | postgresql-9.4-repmgr | postgresql-9.3-repmgr | postgresql-9.2-repmgr | postgresql-9.1-repmgr | postgresql-9.0-repmgr

but repmgr 3.1.5-1 is also in zesty. It shows up at
http://people.canonical.com/~ubuntu-archive/nbs.html and I think we need to manually delete the old binary package.

repmgr NBS binaries removed. This could've been auto-reaped, if the repmgr package didn't declare an alternate dep on binaries that it no longer builds.

Removing packages from zesty:
 postgresql-9.5 9.5.5-0ubuntu1 in zesty
  postgresql-9.5 9.5.5-0ubuntu1 in zesty amd64
  postgresql-9.5 9.5.5-0ubuntu1 in zesty arm64
  postgresql-9.5 9.5.5-0ubuntu1 in zesty armhf
  postgresql-9.5 9.5.5-0ubuntu1 in zesty i386
  postgresql-9.5 9.5.5-0ubuntu1 in zesty powerpc
  postgresql-9.5 9.5.5-0ubuntu1 in zesty ppc64el
  postgresql-9.5 9.5.5-0ubuntu1 in zesty s390x
  postgresql-9.5-dbg 9.5.5-0ubuntu1 in zesty amd64
  postgresql-9.5-dbg 9.5.5-0ubuntu1 in zesty arm64
  postgresql-9.5-dbg 9.5.5-0ubuntu1 in zesty armhf
  postgresql-9.5-dbg 9.5.5-0ubuntu1 in zesty i386
  postgresql-9.5-dbg 9.5.5-0ubuntu1 in zesty powerpc
  postgresql-9.5-dbg 9.5.5-0ubuntu1 in zesty ppc64el
  postgresql-9.5-dbg 9.5.5-0ubuntu1 in zesty s390x
  postgresql-client-9.5 9.5.5-0ubuntu1 in zesty amd64
  postgresql-client-9.5 9.5.5-0ubuntu1 in zesty arm64
  postgresql-client-9.5 9.5.5-0ubuntu1 in zesty armhf
  postgresql-client-9.5 9.5.5-0ubuntu1 in zesty i386
  postgresql-client-9.5 9.5.5-0ubuntu1 in zesty powerpc
  postgresql-client-9.5 9.5.5-0ubuntu1 in zesty ppc64el
  postgresql-client-9.5 9.5.5-0ubuntu1 in zesty s390x
  postgresql-contrib-9.5 9.5.5-0ubuntu1 in zesty amd64
  postgresql-contrib-9.5 9.5.5-0ubuntu1 in zesty arm64
  postgresql-contrib-9.5 9.5.5-0ubuntu1 in zesty armhf
  postgresql-contrib-9.5 9.5.5-0ubuntu1 in zesty i386
  postgresql-contrib-9.5 9.5.5-0ubuntu1 in zesty powerpc
  postgresql-contrib-9.5 9.5.5-0ubuntu1 in zesty ppc64el
  postgresql-contrib-9.5 9.5.5-0ubuntu1 in zesty s390x
  postgresql-doc-9.5 9.5.5-0ubuntu1 in zesty amd64
  postgresql-doc-9.5 9.5.5-0ubuntu1 in zesty arm64
  postgresql-doc-9.5 9.5.5-0ubuntu1 in zesty armhf
  postgresql-doc-9.5 9.5.5-0ubuntu1 in zesty i386
  postgresql-doc-9.5 9.5.5-0ubuntu1 in zesty powerpc
  postgresql-doc-9.5 9.5.5-0ubuntu1 in zesty ppc64el
  postgresql-doc-9.5 9.5.5-0ubuntu1 in zesty s390x
  postgresql-plperl-9.5 9.5.5-0ubuntu1 in zesty amd64
  postgresql-plperl-9.5 9.5.5-0ubuntu1 in zesty arm64
  postgresql-plperl-9.5 9.5.5-0ubuntu1 in zesty armhf
  postgresql-plperl-9.5 9.5.5-0ubuntu1 in zesty i386
  postgresql-plperl-9.5 9.5.5-0ubuntu1 in zesty powerpc
  postgresql-plperl-9.5 9.5.5-0ubuntu1 in zesty ppc64el
  postgresql-plperl-9.5 9.5.5-0ubuntu1 in zesty s390x
  postgresql-plpython-9.5 9.5.5-0ubuntu1 in zesty amd64
  postgresql-plpython-9.5 9.5.5-0ubuntu1 in zesty arm64
  postgresql-plpython-9.5 9.5.5-0ubuntu1 in zesty armhf
  postgresql-plpython-9.5 9.5.5-0ubuntu1 in zesty i386
  postgresql-plpython-9.5 9.5.5-0ubuntu1 in zesty powerpc
  postgresql-plpython-9.5 9.5.5-0ubuntu1 in zesty ppc64el
  postgresql-plpython-9.5 9.5.5-0ubuntu1 in zesty s390x
  postgresql-plpython3-9.5 9.5.5-0ubuntu1 in zesty amd64
  postgresql-plpython3-9.5 9.5.5-0ubuntu1 in zesty arm64
  postgresql-plpython3-9.5 9.5.5-0ubuntu1 in zesty armhf
  postgresql-plpython3-9.5 9.5.5-0ubuntu1 in zesty i386
  postgresql-plpython3-9.5 9.5.5-0ubuntu1 in zesty powerpc
  postgresql-plpython3-9.5 9.5.5-0ubuntu1 in zesty ppc64el
  postgresql-plpython3-9.5 9.5.5-0ubuntu1 in zesty s390x
  postgresql-pltcl-9.5 9.5.5-0ubuntu1 in zesty amd64
  postgresql-pltcl-...