Ignore W503 pep8 warning, it is outdated on our jenkins

Our old version of pep8 produces a warning that goes against
the actual pep8 style guide:
https://www.python.org/dev/peps/pep-0008/#should-a-line-break-before-or-after-a-binary-operator
PyCQA/pycodestyle#498

Change-Id: Iea4612a6608f9de25a1a85c201e5ccc936ec35b7

tox.ini

@@ -8,7 +8,8 @@ envlist = py27, pep8
 max-line-length = 100
 # E123/E133, E226 and E241/E242 are default ignores
 # E402: module level import not at top of file
-ignore = E123,E133,E226,E241,E242,E402
+# W503: ignore operators after line break until pep8 is upgraded
+ignore = E123,E133,E226,E241,E242,E402,W503
 # Upstream files that don't pass flake8 but should not be locally modified
 # jupyterhub_config.py/nchp_config.py are config files & hence won't pass pep8
 exclude = modules/letsencrypt/files/acme_tiny.py,modules/varnish/files/varnishapi.py,modules/postgresql/files/check_postgres_replication_lag.py,modules/jupyterhub/files/jupyterhub_config.py,modules/jupyterhub/files/nchp_config.py