[backportpackage] undocumented --key, --dont-sign options

This bug was fixed in the package ubuntu-dev-tools - 0.143

---------------
ubuntu-dev-tools (0.143) unstable; urgency=low

  [ Iain Lane ]
  * backportpackage: Fix filenames searched when looking for existing
    .orig.tar.foo files (to determine if we need to upload it again or not).
    (LP: #1007908)
  * backportpackage: Unset DEBEMAIL when building source package. Fixes error
    when building backports for packages with no Ubuntu changes.
    (LP: #1007042)

  [ Mathieu Trudel-Lapierre ]
  * mk-sbuild: use and update messages to suggest using the source:$chroot way
    of referring to source chroots instead of $chroot-source; since the latter
    does not work with btrfs snapshot-based chroots. (LP: #1014669)

  [ Lars Düsing ]
  * Corrected brackets in man-page for sponsor-patch.

  [ Stefano Rivera ]
  * pbuilder-dist: Don't try to enable -updates for the current codename
    referring to Debian testing, either (LP: #1011870)
  * Correct spelling mistakes in package description, thanks Logan Rosen for
    the patch (Closes: #678245)
  * Correct metavar for --mirror in backportpackage (LP: #999727)
  * submittodebian: Explitictly UTF-8 encode the bug body (LP: #1005834)
  * backportpackage.1: Document --key and --dont-sign (LP: #1007564)
  * seeded-in-ubuntu: Catch errors in parsing data, and don't keep unreadable
    data cached (LP: #1008783)
  * ubuntutools.archive: Improve error handling around rmadison calls
    (LP: #1010951)
  * submittodebian; Unset DEBEMAIL when building source package.
    (LP: #1015066)

  [ Benjamin Drung ]
  * Add a man page for the reverse-build-depends wrapper script.

 -- Benjamin Drung <email address hidden> Fri, 22 Jun 2012 13:34:43 +0200