Use ansible-lint 2.7.0

ansible-lint 2.7.0 was recently released, update the role's test
requirements to use it.

The tox test has been changed to run ansible-lint against this role,
rather than the test playbook which would only apply to this role's
dependencies.

Also update the 'Drop fernet key auto rotate script' task to use mode
"0755", matching the comment above the task and to resolve a violation
of new rule, [ANSIBLE0009] Octal file permissions must contain leading
zero.

Change-Id: I09396f8938cf8f0b5d48bc5b7215ecea2c426e94

tasks/keystone_fernet_keys_autorotate.yml

@@ -24,7 +24,7 @@
     dest: "{{ keystone_fernet_auto_rotation_script }}"
     owner: "{{ keystone_system_user_name }}"
     group: "{{ keystone_system_group_name }}"
-    mode: "1755"
+    mode: "0755"
   tags:
     - keystone-fernet-auto-rotate
 

test-requirements.txt

@@ -1,4 +1,4 @@
-ansible-lint<=2.3.9
+ansible-lint>=2.7.0,<3.0.0
 ansible>=1.9.1,<2.0.0,!=1.9.6
 bashate
 flake8

tox.ini

@@ -101,7 +101,7 @@ commands =
 
 [testenv:ansible-lint]
 commands =
-    ansible-lint {toxinidir}/tests/test.yml
+    ansible-lint {toxinidir}
 
 
 [testenv:functional]