Enable H302 hacking check

This change requires hacking >0.5.5

Change-Id: Ic36fa0502548335d433f3fbe663854523dd04397

tests/unit/test_jsonutils.py

@@ -19,7 +19,7 @@ import datetime
 import xmlrpclib
 
 import netaddr
-from six import StringIO
+import six
 
 from openstack.common import jsonutils
 from tests import utils
@@ -34,7 +34,7 @@ class JSONUtilsTestCase(utils.BaseTestCase):
         self.assertEqual(jsonutils.loads('{"a": "b"}'), {'a': 'b'})
 
     def test_load(self):
-        x = StringIO('{"a": "b"}')
+        x = six.StringIO('{"a": "b"}')
         self.assertEqual(jsonutils.load(x), {'a': 'b'})