upstart depends on inotify, and overlayfs does not support inotify.

That means that the following results in 'tgt' not running. tgt is simply
used here as an example of a service that installs an upstart job and
starts it on package install.
 lxc-clone -s -B overlayfs -o source-precise-amd64 -n test1
 lxc-start -n test1
 ..
 apt-get install tgt

The change here is to modify /sbin/start inside the container so that when
something explicitly tries 'start', it results in an explicit call to
'initctl reload-configuration' so that upstart is aware of the newly
placed job.

Should overlayfs ever gain inotify support, this should still not cause
any harm.
Signed-off-by: Scott Moser <smoser@ubuntu.com>
Signed-off-by: Serge Hallyn <serge.hallyn@ubuntu.com>