Watch out for ml2 plugin config changes

Restart neutron api service if ml2 plugin config has changed.

Change-Id: I6d5ff1e52a0b37ebf5ae1eb22b4097b543780074
diff --git a/neutron/server.sls b/neutron/server.sls
index 0b3a6be..1ce07ad 100644
--- a/neutron/server.sls
+++ b/neutron/server.sls
@@ -72,6 +72,8 @@
   - template: jinja
   - require:
     - pkg: neutron_server_packages
+  - watch_in:
+    - service: neutron_server_services
 
 ml2_plugin_link:
   cmd.run: