Use tripleo-admin as octavia groups_vars owner

Now we use tripleo-admin as user and it does not have access to
/var/lib/mistral, this change the owner of the group_vars dir to this
user.

Closes-Bug: #1815872

Change-Id: I06b184483a05b7b79b8ccf867b373429e698f396

deployment/octavia/octavia-deployment-config.j2.yaml

@@ -246,9 +246,11 @@ outputs:
               set_fact:
                 octavia_ansible_group_vars: { get_attr: [OctaviaVars, value, vars] }
             - name: Make needed directories on the undercloud
+              become: true
               file:
                 path: "{{item}}"
                 state: directory
+                owner: "{{ ansible_user }}"
               with_items:
                 - "{{ octavia_ansible_group_vars.octavia_local_tmpdir }}"
                 - "{{ octavia_ansible_group_vars.octavia_group_vars_dir }}"