Comment 18 for bug 1627304

The following fix to the abstraction seems to fix the issue:

=== modified file 'data/apparmor/abstractions/lightdm'
--- data/apparmor/abstractions/lightdm 2015-10-19 10:44:23 +0000
+++ data/apparmor/abstractions/lightdm 2016-09-28 03:39:54 +0000
@@ -95,7 +95,7 @@
   unix (receive) peer=(label=unconfined),
   unix (create),
   unix (getattr, getopt, setopt, shutdown),
- unix (bind, listen) type=stream addr="@/com/ubuntu/upstart-session/**",
+ unix (bind, listen, accept, receive, send) type=stream addr="@/com/ubuntu/upstart-session/**",
   unix (bind, listen) type=stream addr="@/tmp/dbus-*",
   unix (bind, listen) type=stream addr="@/tmp/.ICE-unix/[0-9]*",
   unix (bind, listen) type=stream addr="@/dbus-vfs-daemon/*",

I figure that something (Unity?) is now making more use of the upstart session. So we need to allow all operations on it.

I'm not an upstart expert but I figure this is safe to allow?