Make openshift-ansible working dir owned by tripleo-admin

The openshift-ansible tasks are now invoked with the tripleo-admin
user, which doesn't by default have write access to /var/lib/mistral,
but it does have sudo access.

This change makes /var/lib/mistral/<stack>/openshift be owned by the
tripleo-admin user so that subsequent tasks can write to that
directory.

Change-Id: I7762af7b824ae0c7303438d48fc35c9f24a00c9c
Related-Bug: #1813832

extraconfig/services/openshift-master.yaml

@@ -174,6 +174,7 @@ outputs:
           - - name: openshift_master step 1
               when: step == '1'
               tags: openshift
+              become: true
               block:
                 # NOTE(mandre) Remove inventory directory as it may contain
                 # obsolete files that can mess up the current deployment
@@ -189,6 +190,7 @@ outputs:
                   file:
                     path: "{{playbook_dir}}/openshift/inventory"
                     state: directory
+                    owner: "{{ ansible_user }}"
 
             - name: openshift_master step 3
               when: step == '3'