ubuntu-cloud-prep: patch /sbin/start for overlayfs

ubuntu-cloud-prep: patch /sbin/start for overlayfs

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>