Allow multiple reader/writers to UDP DNS Sockets
Allow multiple reader/writers to UDP DNS Sockets

Eventlet would complain loudly about multiple readers/writers
to the UDP DNS socket. As DNS over UDP is single datagram, we
can safely ignore this.

Change-Id: I06c5854de4ea7f5ca48fa6e24efbe8873afc7a8b
Closes-Bug: 1471789

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