Merge pull request #536 from davidt/setting_changed-compat

Fix compatibility with Django < 1.8

pipeline/conf.py

@@ -5,7 +5,11 @@ import collections
 import shlex
 
 from django.conf import settings as _settings
-from django.core.signals import setting_changed
+try:
+    from django.core.signals import setting_changed
+except ImportError:
+    # Django < 1.8
+    from django.test.signals import setting_changed
 from django.dispatch import receiver
 from django.utils.six import string_types