Support mDNS response up to 65k
Support mDNS response up to 65k

Change-Id: Ie2b7306f0201e0f5f51f1bfb5216a778e2bbda65
Closes-Bug: 1435863

cneill/designate,ionrock/designate,cneill/designate-testing,cneill/designate,kiall/designate-py3,ramsateesh/designate,openstack/designate,kiall/designate-py3,tonyli71/designate,muraliselva10/designate,cneill/designate-testing,cneill/designate,cneill/designate,grahamhayes/designate,cneill/designate,openstack/designate,kiall/designate-py3,tonyli71/designate,ionrock/designate,grahamhayes/designate,muraliselva10/designate,grahamhayes/designate,cneill/designate-testing,kiall/designate-py3,tonyli71/designate,muraliselva10/designate,openstack/designate,ramsateesh/designate,ramsateesh/designate,kiall/designate-py3,ionrock/designate