Change django.core.urlresolvers imports

-- compatible with 1.11 --

kfet/auth/signals.py

@@ -1,7 +1,7 @@
 from django.contrib import messages
 from django.contrib.auth.signals import user_logged_in
-from django.core.urlresolvers import reverse
 from django.dispatch import receiver
+from django.urls import reverse
 from django.utils.safestring import mark_safe
 from django.utils.translation import ugettext as _