tox: Disable E501

This is more trouble than it's worth now. Black takes care of this for
us. I wish I'd decided this before the blackify series :(

Change-Id: Ifee786c96b6f0bcd96008fed2b3ed3257d02c07c
Signed-off-by: Stephen Finucane <stephenfin@redhat.com>

Author: stephenfin

tox.ini

@@ -129,8 +129,9 @@ commands =
 show-source = True
 exclude = .venv,.git,.tox,dist,doc,*lib/python*,*egg,build,tools,releasenotes
 # E203 Black will put spaces after colons in list comprehensions
+# E501 Black takes care of line length for us
 # H301 Black will put commas after imports that can't fit on one line
 # W503 and W504 are disabled since they're not very useful
-ignore = E203,H301,W503,W504
+ignore = E203,E501,H301,W503,W504
 import-order-style = pep8
 application_import_names = openstackclient