Switch to Victoria tests

This repo has been using train tests and thus was missed by the bot to
update from ussuri to victoria, update manually.

See also the PTI in governance [1].

Fix pep8 failure in debtcollector/updating.py and remove six from the
file.

[1]: https://governance.openstack.org/tc/reference/project-testing-interface.html

Change-Id: I9d07da7c5729f7ed33cc25f27cf70a7a41d1214c

.zuul.yaml

@@ -3,7 +3,7 @@
       - check-requirements
       - lib-forward-testing-python3
       - openstack-lower-constraints-jobs
-      - openstack-python3-train-jobs
+      - openstack-python3-victoria-jobs
       - periodic-stable-jobs
       - publish-openstack-docs-pti
       - release-notes-jobs-python3

debtcollector/updating.py

@@ -14,19 +14,9 @@
 #    License for the specific language governing permissions and limitations
 #    under the License.
 
-import six
 import wrapt
-if six.PY3:
-    import inspect
-    Parameter = inspect.Parameter
-    Signature = inspect.Signature
-    get_signature = inspect.signature
-else:
-    # Provide an equivalent but use funcsigs instead...
-    import funcsigs
-    Parameter = funcsigs.Parameter
-    Signature = funcsigs.Signature
-    get_signature = funcsigs.signature
+
+from inspect import signature
 
 from debtcollector import _utils
 
@@ -48,8 +38,8 @@ def updated_kwarg_default_value(name, old_value, new_value, message=None,
         prefix, postfix=postfix, message=message, version=version)
 
     def decorator(f):
-        sig = get_signature(f)
-        varnames = list(six.iterkeys(sig.parameters))
+        sig = signature(f)
+        varnames = list(sig.parameters.keys())
 
         @wrapt.decorator
         def wrapper(wrapped, instance, args, kwargs):