Don't configure external bridge on computes if DVR is disabled

Change-Id: I9978cb714e423863afd5b892419f4176b6d73d92
Closes-Bug: #1686761

ansible/roles/openvswitch/handlers/main.yml

@@ -34,6 +34,9 @@
   command: docker exec openvswitch_db /usr/local/bin/kolla_ensure_openvswitch_configured {{ item.0 }} {{ item.1 }}
   register: status
   changed_when: status.stdout.find('changed') != -1
+  when:
+    - inventory_hostname in groups["network"]
+      or (inventory_hostname in groups["compute"] and enable_neutron_dvr | bool)
   with_together:
     - "{{ neutron_bridge_name.split(',') }}"
     - "{{ neutron_external_interface.split(',') }}"