Fix up ovn-dbs update tasks

Noticed master failing with:
2020-08-18 07:16:16.346959 | 00a673e5-dc44-c6b1-ce2d-000000000094 |
FATAL | Update the ovn-dbs-bundle to use the new container image name | overcloud-controller-0 | error={"msg": "The conditional check
'ovn_dbs_current_image.stdout != ovn_dbs_image_latest' failed. The error was: error while evaluating conditional (ovn_dbs_current_image.stdout !=
ovn_dbs_image_latest): 'ovn_dbs_image_latest' is undefined\n\nThe error appears to be in '/tmp/tripleo5rvsi_ix/overcloud/Controller/update_tasks_step5.yaml':
line 23, column 7, but may\nbe elsewhere in the file depending on the
exact syntax problem.\n\nThe offending line appears to be:\n\n  - block:\n    - command: pcs resource bundle update ovn-dbs-bundle
container image={{ovn_dbs_image_latest}}\n      ^ here\nWe could be wrong, but this one looks like it might be an issue with\nmissing
quotes. Always quote template expression brackets when they\nstart a value. For instance:\n\n    with_items:\n      - {{ foo }}\n\nShould be
written as:\n\n    with_items:\n      - \"{{ foo }}\"\n"}

Tested a minor update with this patch and I did not hit the error
anymore.

Closes-Bug: #1892042

Change-Id: I875a0753686669b16d0ceb25e6e5692c150d6a79
(cherry picked from commit e892d40046)

deployment/ovn/ovn-dbs-pacemaker-puppet.yaml

@@ -347,6 +347,8 @@ outputs:
                   command: "pcs resource bundle update ovn-dbs-bundle container image={{ovn_dbs_image_latest}}"
               when:
                 - ovn_dbs_current_image.stdout != ovn_dbs_image_latest
+          vars:
+            ovn_dbs_image_latest: *ovn_dbs_image_pcmklatest
 
       upgrade_tasks:
         - name: Prepare switch of ovn-dbs image name