Change django.core.urlresolvers imports

-- compatible with 1.11 --

kfet/tests/testcases.py

@@ -1,9 +1,9 @@
 from unittest import mock
 from urllib.parse import parse_qs, urlparse
 
-from django.core.urlresolvers import reverse
 from django.http import QueryDict
 from django.test import Client
+from django.urls import reverse
 from django.utils import timezone
 from django.utils.functional import cached_property