If node joins the cluster after application master instance

If node joins the cluster after application master instance
is selected, it doesn't get any notification about the ownership
change of the application, so it does not initiate the ovsdb manager,
It should check if any other instance is master instance,
if yes, consider itself slave and start the Ovsdb Manager.

Patch 2: Register entity ASAP, to minimize the delta for missing
ownership change notifications
Patch 3: Fixed unit test

Change-Id: Iea205de0a760f3e03962bb889e82acacfbf2247b
Signed-off-by: Anil Vishnoi <vishnoianil@gmail.com>