Comment 1 for bug 1199778

This problem affects those systems hosting chroots but also affects those with sbuild/pbuilder installed. The failure process is as follows:

- user builds a package in the sbuild/pbuilder env.
- upstart gets updated within the sbuild/pbuilder chroot as part of the package build.
- as part of the upgrade, the Upstart maintainer script gets called which calls "initctl version" crucially *before* ischroot gets
  called.
- at this stage an upstart session now exists for the chroot on the host system.
- the version of upstart gets upgraded on the host system (*)
- the upgrade triggers a stateful re-exec.
- seemingly on deserialisation, if sessions exist in the meta-data, a crash results.