When a VM is migrated that has a floating IP associated, the L3
agent on the source host should be notified when the migration
is over. If the router on the source host is not going to be
removed (there are other ports using it) then we should nofity
that the floating IP needs to be cleaned up.
Closes-bug: #1585165
(cherry picked from commit a1f06fd707)
Conflicts:
neutron/db/l3_dvrscheduler_db.py
neutron/tests/unit/scheduler/test_l3_agent_scheduler.py
Change-Id: Iad6fbad06cdd33380ef536e6360fd90375ed380d