Fix and enable F811 pep8 rule (redefinitions)

Change-Id: I4578a6ee77e2c875fa0be03763a5176fc0075198
Related-Bug: #1333290

manilaclient/v1/client.py

@@ -10,7 +10,7 @@
 # License for the specific language governing permissions and limitations
 # under the License.
 
-from manilaclient import client
+from manilaclient import client as httpclient
 from manilaclient.v1 import limits
 from manilaclient.v1 import quota_classes
 from manilaclient.v1 import quotas
@@ -68,7 +68,7 @@ class Client(object):
                     setattr(self, extension.name,
                             extension.manager_class(self))
 
-        self.client = client.HTTPClient(
+        self.client = httpclient.HTTPClient(
             username,
             password,
             project_id,

tests/v1/test_shell.py

@@ -440,7 +440,7 @@ class SecretsHelperTestCase(utils.TestCase):
             return_value='fake_token|fake_url|fake_tenant_id')).start()
         self.addCleanup(mock.patch.stopall)
 
-    def test_validate_string_void_string(self):
+    def test_validate_string_empty_string(self):
         self.assertFalse(self.helper._validate_string(''))
 
     def test_validate_string_void_string(self):
@@ -510,7 +510,7 @@ class SecretsHelperTestCase(utils.TestCase):
         self.helper = shell.SecretsHelper(self.args, self.cs.client)
         self.assertIsNone(self.helper.auth_token)
 
-    def test_management_url_os_cache_true(self):
+    def test_auth_token_os_cache_true(self):
         self.assertEqual(self.helper.auth_token, 'fake_token')
         expected_key = 'http://111.11.11.11:5000/user/project/region/' \
                        'publicURL/share/fake/fake'

tox.ini

@@ -28,6 +28,7 @@ commands = python setup.py testr --coverage --testr-args='{posargs}'
 downloadcache = ~/cache/pip
 
 [flake8]
-ignore = F811,F821
+# F821: undefined name
+ignore = F821
 builtins = _
 exclude = .venv,.tox,dist,doc,openstack,*egg