s/django.core.urlresolvers/django.urls/g

Django 1.10 deprecation fix for Hackathon XIX
Addresses PLAT-1397

openedx/core/djangoapps/cache_toolbox/tests/test_middleware.py

@@ -1,6 +1,6 @@
 """Tests for cached authentication middleware."""
 from django.contrib.auth.models import User
-from django.core.urlresolvers import reverse
+from django.urls import reverse
 from django.test import TestCase
 from mock import patch