[ffwd3] Upgrade ovn_controller ahead

Normally we would use deployment steps to upgrade service
but ovn_controller has to be upgraded before ovn_dbs and
ovn_dbs gets deployed in step3 same as ovn_controller.

Originally we moved ovn_controller from step4 to step3 to
resolve the issue but this still creates race. Solution
would be to move all steps in ovn_dbs one up or ovn_controller
one lower but all in all steps in tripleo don't give us enough
flexibility for this.

We already have hack dance around ovn_controller during update
which forces the ovn_controller as external update run before
all other actions during update. We can reuse this code and just
trigger it during upgrade.

Resolves: rhbz#2229761

Change-Id: I7a04ce318038ea632261726b198ef9b2497446dd

deployment/ovn/ovn-controller-container-puppet.yaml

@@ -514,7 +514,7 @@ outputs:
                       $ROLE_NAME: {get_param: RoleName}
                 ovn_bridge_mappings: {get_attr: [OVNBridgeMappingsValue, value, ovn_bridge_mappings]}
                 ovn_static_bridge_mac_mappings: {get_attr: [OVNBridgeMappingsValue, value, ovn_static_bridge_mac_mappings]}
-      external_update_tasks:
+      external_update_tasks: &ovn_controller_update
         - name: Force pull image in case image name doesn't change.
           when: step|int == 1
           tags:
@@ -641,7 +641,7 @@ outputs:
           until: async_poll_results.finished
           retries: {get_param: OVNControllerUpdateTimeout}
           delay: 1
-      upgrade_tasks: []
+      upgrade_tasks: *ovn_controller_update
       scale_tasks:
         - when:
             - step|int == 1