BUG-7215: Fix App Peer ModifiedNodeDoesNotExistException

BUG-7215: Fix App Peer ModifiedNodeDoesNotExistException

If Rib is reconfigured with different Family than the
previous supported one, application peer will be
reconfigured. In the case there are some routes or,
family table configured on Config DS, when restarting
App peer with new configuration will end on
ModifiedNodeDoesNotExistException.

Fix by:
   -Make Application peer more defensiveness by ingore changes
 on config DS for non supported Families.
   - Register Change Listener once AdjRibIn has been
 succesfully initialized.

Change-Id: I25b08b057fad02df365070c0a6d5177b9e0392a0
Signed-off-by: Claudio D. Gasparini <cgaspari@cisco.com>