Install Neutron services prior to client state

It was found that if neutron flat network is being created
when neutron-openvswitch-agent is not running the network
and subnet are created without errors however the corresponding
neutron port will be in unusable state - binding:vif_type parameter
will have "binding_failed" value and port admin state will be DOWN.
More information could be found on the following link:
https://bugs.launchpad.net/neutron/+bug/1399249
As a result full neutron state is invoked on neutron:gateway nodes and
neutron.client state invocation order was changed to ensure it runs
after neutron agents are installed

Related-PROD: PROD-18590

(cherry picked from commit c4a485e1b7beac338e036b444be16ba2b3efa25c)
Change-Id: I9031c844519a34d7355cbeb134610fbe93c60503
1 file changed