Fix ansible-lint test failures

With the merge of https://review.openstack.org/520177 in the
tests repo some ansible-lint failures which previously were
not being picked up are now detected.

Change-Id: I2c1720056046f038cfeae3b0591230ab1aa5e5ac

tests/test-install-designate.yml

@@ -35,7 +35,7 @@
         dest: "{{ named_config_file }}"
     - name: fix perms for named directory (centos)
       file:
-        mode: '770'
+        mode: '0770'
         state: directory
         path: '/var/named/'
         owner: 'root'