Update hacking for Python3

The repo is Python 3 now, so update hacking to version 3.0 which
supports Python 3.

Fix problems found.

Change-Id: I5a4123c0c5e18c0e25383491253299fc5b54618b

cloudkittydashboard/overrides.py

@@ -34,4 +34,5 @@ class InstancePredictivePricing(create_instance.SetInstanceDetailsAction):
                       self).get_help_text(extra_context=extra)
         return extra
 
+
 create_instance.SetInstanceDetails.action_class = InstancePredictivePricing

test-requirements.txt

@@ -1,7 +1,8 @@
 # The order of packages is significant, because pip processes them in the order
 # of appearance. Changing the order has an impact on the overall integration
 # process, which may cause wedges in the gate later.
-hacking>=1.1.0,<1.2.0 # Apache-2.0
+
+hacking>=3.0.1,<3.1.0 # Apache-2.0
 coverage>=3.6
 python-subunit>=0.0.18
 oslotest>=1.10.0 # Apache-2.0

tox.ini

@@ -2,6 +2,7 @@
 minversion = 2.0
 envlist = py36,py37,pep8
 skipsdist = True
+ignore_basepython_conflict = True
 
 [testenv]
 basepython = python3