In some cases, the arp entry of snat port is not updated
in qrouter namespace. l3-agent calls get_ports_by_subnet()
while setting arps for the subnet. And the snat port is
not returned if it is still unbound. One of the scenario
this is observed is when router is created, external
gateway set and internal subnet attached to router in
quick succession.
This patch retrieves snat port details from router info
as well and updates arp entry for snat port.
Conflicts:
neutron/agent/l3/dvr_local_router.py
Closes-Bug: #1933092
Change-Id: I7ee797b4b930306cf6360922d855f8b24f1b813d
(cherry picked from commit be7d0bb6ab)
(cherry picked from commit f1a9f4ed62)