Update hacking for Python3

The repo is Python 3 now, so update hacking to version 3.1.0 which
supports Python 3.

Fix problems found.

Remove hacking and friends from lower-constraints, they are not needed
for installation.

Change-Id: I810e4c30513746bc46a3e65b398539929a7ac6b0

lower-constraints.txt

@@ -10,12 +10,10 @@ eventlet==0.18.2
 extras==1.0.0
 fasteners==0.7.0
 fixtures==3.0.0
-flake8==2.5.5
 futurist==1.2.0
 gitdb==0.6.4
 GitPython==1.0.1
 greenlet==0.4.10
-hacking==0.12.0
 iso8601==0.1.11
 Jinja2==2.10
 jsonschema==2.6.0
@@ -23,7 +21,6 @@ keystoneauth1==3.4.0
 kombu==4.0.0
 linecache2==1.0.0
 MarkupSafe==1.0
-mccabe==0.2.1
 mox3==0.20.0
 msgpack-python==0.4.0
 netaddr==0.7.18
@@ -43,11 +40,9 @@ oslotest==3.2.0
 Paste==2.0.2
 PasteDeploy==1.5.0
 pbr==2.0.0
-pep8==1.5.7
 pika==0.10.0
 pika-pool==0.1.3
 prettytable==0.7.2
-pyflakes==0.8.1
 pyinotify==0.9.6
 pyparsing==2.1.0
 python-dateutil==2.5.3

oslo_versionedobjects/test.py

@@ -23,19 +23,19 @@ Some black magic for inline callbacks.
 import eventlet  # noqa
 eventlet.monkey_patch(os=False)  # noqa
 
-import functools
-import inspect
-import os
-from unittest import mock
+import functools   # noqa: E402
+import inspect   # noqa: E402
+import os   # noqa: E402
+from unittest import mock   # noqa: E402
 
-import fixtures
-from oslo_concurrency import lockutils
-from oslo_config import cfg
-from oslo_config import fixture as config_fixture
-from oslo_log.fixture import logging_error
-import testtools
+import fixtures   # noqa: E402
+from oslo_concurrency import lockutils   # noqa: E402
+from oslo_config import cfg   # noqa: E402
+from oslo_config import fixture as config_fixture   # noqa: E402
+from oslo_log.fixture import logging_error   # noqa: E402
+import testtools   # noqa: E402
 
-from oslo_versionedobjects.tests import obj_fixtures
+from oslo_versionedobjects.tests import obj_fixtures   # noqa: E402
 
 
 CONF = cfg.CONF

test-requirements.txt

@@ -1,7 +1,7 @@
 # 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>=2.0.0,<2.1.0 # Apache-2.0
+hacking>=3.1.0,<3.2.0 # Apache-2.0
 oslotest>=3.2.0 # Apache-2.0
 testtools>=2.2.0 # MIT
 coverage!=4.4,>=4.0 # Apache-2.0