set USE_TZ=True in runtests to handle fixtures correctly on sqlite

runtests.py

@@ -42,6 +42,7 @@ if not settings.configured:
         STATIC_URL='/static/',
         STATIC_ROOT=STATIC_ROOT,
         MEDIA_ROOT=MEDIA_ROOT,
+        USE_TZ=True,
         STATICFILES_FINDERS=(
             'django.contrib.staticfiles.finders.AppDirectoriesFinder',
             'compressor.finders.CompressorFinder',