EXT-38, use neutron port ip instead of subnet gateway ip
EXT-38, use neutron port ip instead of subnet gateway ip

Change-Id: I6be8bd845c8a322a548a01e81699d67d7f2cbc03

stackforge/networking-bigswitch,openstack/networking-bigswitch,stackforge/networking-bigswitch,wolverineav/networking-bigswitch,openstack/networking-bigswitch,wolverineav/networking-bigswitch