Limit ovn sanity checks to q-svc
Limit ovn sanity checks to q-svc

The sanity checks related to neutron-server config only make sense
when q-svc service is enabled. When building a devstack without q-svc
(for example a compute-only devstack) do not force this configuration
to be present where it's meaningless.

Change-Id: I5b9176d4a55a826f498e367f1f02569429dbe546

mahak/neutron,mahak/neutron,openstack/neutron,openstack/neutron,mahak/neutron,openstack/neutron