Fixed a number of flake8 errors -- particularly around unused imports and local variables

django/template/defaulttags.py

@@ -54,7 +54,6 @@ class CsrfTokenNode(Node):
         else:
             # It's very probable that the token is missing because of
             # misconfiguration, so we raise a warning
-            from django.conf import settings
             if settings.DEBUG:
                 warnings.warn("A {% csrf_token %} was used in a template, but the context did not provide the value.  This is usually caused by not using RequestContext.")
             return ''