Run db-sync before we manage neutron services

This commit puts in place a dependency between db-sync and the
  neutron-ovs-agent-service service.

  This is specially being done because in Puppet 4 tests we are seeing
  the neutron-ovs-agent-service trying to start before the int-br-ex
  related rows are being added to the neutron db.

Change-Id: Ifc3f40ae1cb71c215b8a0bf6cd5f6d05101a6168

manifests/agents/ml2/ovs.pp

@@ -297,7 +297,7 @@ class neutron::agents::ml2::ovs (
     name    => $::neutron::params::ovs_agent_service,
     enable  => $enabled,
     require => Class['neutron'],
-    tag     => 'neutron-service',
+    tag     => ['neutron-service', 'neutron-db-sync-service'],
   }
 
   if $::neutron::params::ovs_cleanup_service {

spec/classes/neutron_agents_ml2_ovs_spec.rb

@@ -75,7 +75,7 @@ describe 'neutron::agents::ml2::ovs' do
         :enable  => true,
         :ensure  => 'running',
         :require => 'Class[Neutron]',
-        :tag     => 'neutron-service',
+        :tag     => ['neutron-service', 'neutron-db-sync-service'],
       )
       is_expected.to contain_service('neutron-ovs-agent-service').that_subscribes_to( [ 'Package[neutron]', 'Package[neutron-ovs-agent]' ] )
     end