lib: Trigger callbacks to re-evaluate route-map clauses when "call" CLI is executed.

lib: Trigger callbacks to re-evaluate route-map clauses when "call" CLI is executed.

When the "call" CLI is executed from with-in a route-map that is already in use,
there is a need to get the route-map clients to re-evalute the clauses defined
by both the parent route-map, as well as the child route-map.
The existing callbacks, add_hook() and delete_hook() can be used by the lib to
inform the clients when the "call" is configured and unconfigured.

Signed-off-by: NaveenThanikachalam <nthanikachal@vmware.com>