Exclude router gw subnet ports from port list while port delete.
Exclude router gw subnet ports from port list while port delete.

During port delete Neutron checks if host still handle some ports
from subnets that are used by router.

It may happen that the same subnet that is used for router gateway
port may be used for another VM port. Then we skip notification
to update L3 agent about related to router port deletion.

Related-Bug: #1957794
Change-Id: Iacc7d4e543ac261a6f566b49834b6865f6eded95

openstack/neutron,openstack/neutron,mahak/neutron,mahak/neutron,openstack/neutron,mahak/neutron