Remove Devstack workaround for Neutron
Remove Devstack workaround for Neutron

Feature of Neutron DNS resolvers was disabled as
unsupported by manila-service-image.
Enable it, since, it is supported now [1].

[1] Icf7f189d621e9686c4bb449b5770b83e4bd072ee

Change-Id: I667c811c752864d6d7f239e2dfd4597e8ac98cb1

vponomaryov/manila,vponomaryov/manila,bswartz/manila,bswartz/manila,openstack/manila,NetApp/manila,NetApp/manila,openstack/manila