When user is using keepalived on their instances, he often creates
additional port in Neutron to allocate some IP address which will
be then used as VIP in keepalived and will be configured in
allowed_address_pair of other ports plugged to instances with
keepalived.
This is e.g. Octavia's use case.
This together with DVR caused problems with connectivity to such VIP
as it was populated in router's arp cache with MAC address from
Neutron db.
As this port isn't bound, it is only Neutron db entry so there is no
need to set it in arp cache of the router.
This patch is doing exactly that to filter such "unbound" and
"binding_failed" ports from the list.
Change-Id: Ia885ce00dbb5f2968859e8d0850bc511016f0846
Closes-Bug: #1869887
eb775458c6