Make /var/lib/mistral traversable by all users

Some tasks in tripleo-ansible (like tripleo_ceph_work_dir/tasks/prepare.yml)
need to be able to run the global inventory from /var/lib/mistral/$id and
refer to it using {{ playbook_dir }} so we need to make the directory
traversable by the ansible_ssh user

Closes-Bug: #1873081
Change-Id: I388b353e5a1f0b79a711ef5c97d0f3ae8b0de44c

deployment/mistral/mistral-executor-container-puppet.yaml

@@ -220,7 +220,7 @@ outputs:
             mode: "{{ item.mode|default(omit) }}"
           with_items:
             - { 'path': /var/log/containers/mistral, 'setype': container_file_t, 'mode': '0750' }
-            - { 'path': /var/lib/mistral, 'setype': container_file_t }
+            - { 'path': /var/lib/mistral, 'setype': container_file_t, 'mode': '0751' }
         - name: create mistral/.ssh directory
           file:
             path: /var/lib/mistral/.ssh