ci: Don't enable router-ovn

We are currently using the ML2-OVS neutron, not ML2-OVN. It doesn't make
sense to enable the router-ovn service and should actually result in an
error [1]. Don't do it.

[1] https://bugs.launchpad.net/neutron/+bug/1997970

Signed-off-by: Stephen Finucane <stephenfin@redhat.com>

hack/ci/cloud-init/controller.yaml.tpl

@@ -82,7 +82,7 @@
 
     [[post-config|$NEUTRON_CONF]]
     [DEFAULT]
-    service_plugins = ovn-router,trunk, router
+    service_plugins = trunk,router
 - path: /tmp/register-worker.sh
   permissions: 0755
   content: |