Enable H305 and H307 style checks

Correct grouping and ordering of imports

Change-Id: I47ea0d53f80d7f0aeb01c1c6afd63713be87ddf4
diff --git a/scenario/test_volumes.py b/scenario/test_volumes.py
index fe9ec03..841a091 100644
--- a/scenario/test_volumes.py
+++ b/scenario/test_volumes.py
@@ -11,10 +11,10 @@
 #    under the License.
 
 import logging
-import six
-from testtools import testcase
 
 from cinderclient import exceptions as cinder_exceptions
+import six
+from testtools import testcase
 
 from heat_integrationtests.common import exceptions
 from heat_integrationtests.common import test