Add pep8 job for code style checking

Change-Id: I05f9ba7a414a27a40b278b2c08ce50ac0805f3b6

.zuul.yaml

@@ -1,3 +1,7 @@
 - project:
-    templates:
-      - noop-jobs
+    check:
+      jobs:
+      - openstack-tox-pep8
+    gate:
+      jobs:
+      - openstack-tox-pep8

tox.ini

@@ -44,9 +44,36 @@ commands =
 commands = oslo_debug_helper {posargs}
 
 [flake8]
-# E123, E125 skipped as they are invalid PEP-8.
-
 show-source = True
-ignore = E123,E125
+# E123, E125 skipped as they are invalid PEP-8.
+# Temporarily ignoring these warnings
+# W503: line break before binary operator
+# E116: unexpected indentation (comment)
+# E128: continuation line under-indented for visual indent
+# E402: module level import not at top of file
+# E501: line too long (>79 characters)
+# E704: multiple statements on one line (def)
+# E722: do not use bare except, specify exception instead
+# E731: do not assign a lambda expression, use a def
+# E741: do not use variables named 'l', 'O', or 'I'
+# F401: Module imported but unused
+# F403: 'from module import *' used; unable to detect undefined names
+# F811: redefinition of unused variable
+# F812: list comprehension redefines name from line
+# F821: undefined name '<name>'
+# F841: local variable '<variable>' is assigned to but never used
+# H101: Include your name with TODOs as in ``# TODO(yourname)``
+# H102: Apache 2.0 license header not found
+# H104: Files with no code shouldn't contain any license header nor comments
+# H105: Don't use author tags. We use version control instead.
+# H201: Do not write ``except:``, use ``except Exception:`` at the very least.
+# H301: Do not import more than one module per line (*)
+# H306: Alphabetically order your imports by the full module path
+# H401: Docstrings should not start with a space.
+# H403: Multi line docstrings should end on a new line.
+# H404: Multi line docstrings should start without a leading new line.
+# H405: Multi line docstrings should start with a one line summary followed by an empty line.
+# H501: Do not use ``locals()`` or ``self.__dict__`` for formatting strings
+ignore = E123,E125,W503,E116,E128,E402,E501,E704,E722,E731,E741,F401,F403,F811,F812,F821,F841,H101,H102,H104,H105,H201,H301,H306,H401,H403,H404,H405,H501
 builtins = _
-exclude=.venv,.git,.tox,dist,doc,*lib/python*,*egg,build
+exclude=.venv,.git,.tox,dist,doc,*lib/python*,*egg,build,tools,os_ken/contrib