container-detect.conf should be 'start on virtual-filesystems'

marked as also-affects resolvconf as /etc/init/resolvconf.conf also is start on mounted MOUNTPOINT=/run

now that i think about it there is a race if we back resolvconf.conf to start on virtual-filesystems.
in that as soon as that event occurs networking could come up before resolvconf has had a chance to prep itself.

one othe rpiece of this puzzle is that /etc/init/iscsi-network-interface.conf is doing some magic to stop the interface from getting bounced.

A careful examination of the container-detect job shows that switching it to virtual-filesystems would also result in a race condition. The job has two functions:
 - emitting an event telling whether we're in a container or not
 - populating /run/container_type

The first function is race-free by definition. The second would be racy because the file is consumed by /bin/running-in-container, which is in turn used by /lib/init/apparmor-profile-load, needed by several other upstart jobs to determine whether the apparmor profile needs to be loaded. In the non-container case there's no problem; in the container case, there's a race because these jobs may be started in parallel to the virtual-filesystems processing, check for /run/container_type before it's written, and fail to start because of an apparmor failure.

So unfortunately I don't think we can change this. Instead, this devolves into bug #1031065 / bug #643289, which would also solve this problem once the MOUNTPOINT=/ event was not blocking the MOUNTPOINT=/run event from happening in parallel.