Don't expect nova-network is up if Neutron is used

If we use Neutron as network provider for OpenStack
cloud, nova-network service is not enabled on compute
nodes, so we should expect 14 Nova services are running
instead of 16.

Change-Id: Ie929d1c1f46dc11000c1b06469dafa5c8aaed330
Closes-bug: #1372056