[1.7.x] Removed a flake8 exclude that caused code to be missed.

Backport of 2fa2068 from master

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,./django/utils/dictconfig.py,./django/contrib/comments/*,./django/utils/unittest.py,./django/utils/lru_cache.py,./tests/comment_tests/*,./django/test/_doctest.py,./django/utils/six.py,./django/conf/app_template/*,./django/dispatch/weakref_backports.py,./tests/.env,./xmlrunner,./tests/test_*.py
+exclude=build,.git,./django/utils/dictconfig.py,./django/contrib/comments/*,./django/utils/unittest.py,./django/utils/lru_cache.py,./tests/comment_tests/*,./django/test/_doctest.py,./django/utils/six.py,./django/conf/app_template/*,./django/dispatch/weakref_backports.py,./tests/.env,./xmlrunner
 ignore=E123,E128,E265,E501,W601
 
 [metadata]