upstart should consult /usr/sbin/policy-rc.d

When creating Lucid chroots from my Oneiric host, the dev mount in the chroot cannot be unmounted because some daemons still have some devices open. Only the daemons invoked through upstart are causing problems. In my case that means acpid and openssh-server. The acpid package was changed in latter version (Oneiric at least) to use "invoke-rc.d" instead of "start" but the Lucid version is still causing problems.

Instead of fixing all the potential daemons, I think the best solution would be to have upstart consulting /usr/sbin/policy-rc.d.

I am aware that "/sbin/init" can be diverted but setting both policy-rc.d to return 101 and diverting init seems like redundant.

$ lsb_release -rd
Description: Ubuntu 10.04.4 LTS
Release: 10.04

$ apt-cache policy upstart
upstart:
  Installed: 0.6.5-8
  Candidate: 0.6.5-8
  Version table:
 *** 0.6.5-8 0
        500 http://archive.ubuntu.com/ubuntu/ lucid-updates/main Packages
        100 /var/lib/dpkg/status
     0.6.5-6 0
        500 http://archive.ubuntu.com/ubuntu/ lucid/main Packages