TrivialFix: Delete virtual bridge artifacts when cleaning hosts

After cleaning hosts by using tools/cleanup_host, some of the ovs bridge
devices such as ovs-system still exist. This will result in
{{neutron_external_interface}} not working properly because it had been
added to the ovs-system bridge. The solution is calling
neutron-ovs-cleanup script in neutron_openvswitch_agent container before
removing it.

TrivialFix

Change-Id: Ib3b096d842f2210b8bd223892a3492ef2fcf7c52
Signed-off-by: luyao <lu.yao135@zte.com.cn>

tools/cleanup-containers

@@ -16,6 +16,11 @@ else
         egrep -v '(^\s*$)' | sort | uniq)
 fi
 
+echo "Removing ovs bridge..."
+(docker exec -u root neutron_openvswitch_agent neutron-ovs-cleanup \
+    --config-file /etc/neutron/neutron.conf --config-file /etc/neutron/plugins/ml2/ml2_conf.ini \
+    --ovs_all_ports) > /dev/null
+
 echo "Stopping containers..."
 (docker stop -t 2 ${containers_to_kill} 2>&1) > /dev/null