Add extension_drivers = port_security in neutron.pp

Now when set network port_security_enabled to false,
return  {"NeutronError": {"message": "Unrecognized attribute(s)
'port_security_enabled'", "type": "HTTPBadRequest", "detail": ""}}

Change-Id: If59d1b25c557eebb8a9b9db24e7bd209373d6720

manifests/neutron.pp

@@ -138,6 +138,7 @@ class openstack_integration::neutron (
   class { '::neutron::plugins::ml2':
     type_drivers         => ['vxlan', 'flat'],
     tenant_network_types => ['vxlan', 'flat'],
+    extension_drivers    => 'port_security',
     mechanism_drivers    => $driver,
     firewall_driver      => $firewall_driver,
   }