gluster: Add gluster hook to missing servers

Add gluster hook based on engine's copy of hook
content and status to servers in cluster where the
hook is missing.
If hook is added successfully, remove the gluster
server hook entry for this server.

Change-Id: I6a9b47b18e6fffc43393fdcf09f09f714f734b3d
Signed-off-by: Sahina Bose <sabose@redhat.com>