[Merge] lp:~stgraber/upstart/upstart-session-socket into lp:upstart

[Stéphane Graber]

I replaced the nih_strcat_sprintf by a nih_strdup.

I also dropped some changes to main.c that weren't relevant after the clear split between use_session_bus and user_session. That makes "/sbin/init --user --session" now possible.

And added two tests:
 - Check that initctl connects to the user bus when user_mode is set to TRUE and UPSTART_SESSION is set.
 - Check that initctl fails when user_mode is set to TRUE and UPSTART_SESSION isn't set.

I also updated the manpage to reflect the change in behaviour (now matching the spec).

-- 
https://code.launchpad.net/~stgraber/upstart/upstart-session-socket/+merge/143344
Your team Upstart Reviewers is subscribed to branch lp:upstart.