[Merge] lp:~jamesodhunt/upstart/bug-1199778 into lp:upstart

[James Hunt]

To test this change:

- boot system
- sudo chroot /some/where
- inside chroot, run "initctl list"
- exit chroot
- run get_state.sh (*) like this:
  sudo get_state.sh | json_pp | grep -A 5 "\"sessions\"" 
- check to ensure a session is displayed
- sudo telinit u
- run get_state.sh (*) like this:
  sudo get_state.sh | json_pp | grep -A 5 "\"sessions\"" 
- check to ensure a session is no longer displayed (since although sessions are serialised, we do not currently support their deserialisation).


(*) - http://people.canonical.com/~jhunt/upstart/scripts/get_state.sh
-- 
https://code.launchpad.net/~jamesodhunt/upstart/bug-1199778/+merge/174138
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