Update hacking for Python3

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

Fix problems found by updated hacking version.

Change-Id: I4a4ec207f87d3afb58b6427825ce9b3872823008

os_api_ref/__init__.py

@@ -206,6 +206,7 @@ class RestMethodDirective(rst.Directive):
 
         return [target, section]
 
+
 # cache for file -> yaml so we only do the load and check of a yaml
 # file once during a sphinx processing run.
 YAML_CACHE = {}
@@ -331,7 +332,7 @@ class RestParametersDirective(Table):
                     else:
                         continue
 
-        if len(self.env.path_params) is not 0:
+        if len(self.env.path_params) != 0:
             # Warn that path parameters are not set in rest_parameter
             # stanza and will not appear in the generated table.
             for param in self.env.path_params:

test-requirements.txt

@@ -2,7 +2,7 @@
 # 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,<3.1.0 # Apache-2.0
 
 coverage!=4.4,>=4.0 # Apache-2.0
 python-subunit>=1.0.0 # Apache-2.0/BSD

tox.ini

@@ -36,6 +36,6 @@ commands = oslo_debug_helper {posargs}
 [flake8]
 # E123, E125 skipped as they are invalid PEP-8.
 show-source = True
-ignore = E123,E125,E129
+ignore = E123,E125,E129,W504
 builtins = _
 exclude=.venv,.git,.tox,dist,doc,*openstack/common*,*lib/python*,*egg,build