Only install packages and create bridges if operating in legacy mode

hooks/charmhelpers/contrib/openstack/context.py

@@ -891,8 +891,6 @@ class NeutronContext(OSContextGenerator):
         return ctxt
 
     def __call__(self):
-        self._ensure_packages()
-
         if self.network_manager not in ['quantum', 'neutron']:
             return {}
 

hooks/nova_compute_context.py

@@ -444,6 +444,8 @@ class NeutronComputeContext(context.NeutronContext):
         if not ovs_ctxt:
             return {}
 
+        if config('manage-neutron-plugin-legacy-mode'):
+            self._ensure_packages()
             self._ensure_bridge()
 
         ovs_ctxt['local_ip'] = \