Removed xmlrunner from flake8 exclude.

This is an obsolete thing that Jenkins builds needed.

setup.cfg

@@ -3,7 +3,7 @@ doc_files = docs extras AUTHORS INSTALL LICENSE README.rst
 install-script = scripts/rpm-install.sh
 
 [flake8]
-exclude = build,.git,.tox,./django/utils/six.py,./django/conf/app_template/*,./tests/.env,./xmlrunner
+exclude = build,.git,.tox,./django/utils/six.py,./django/conf/app_template/*,./tests/.env
 ignore = W601
 max-line-length = 119