There are some extreme conditions which will result the unbound
router gateway port. Then all the centralized floating IPs will
not be reachable since the gateway port was set to 4095 tag.
This patch adds the HA status to the router related port
processing code path. If it is HA router, the gateway port
will go to the right HA router processing code branch.
Closes-Bug: #1827754
Change-Id: Ida1c9f3a38171ea82adc2f11cb17945d6e2434be