Fixed DjangoFilterBackend not returning a query set.

Fixed bug unveiled in #682.

Signed-off-by: Kevin Stone <kevinastone@gmail.com>

rest_framework/filters.py

@@ -55,6 +55,6 @@ class DjangoFilterBackend(BaseFilterBackend):
         filter_class = self.get_filter_class(view)
 
         if filter_class:
-            return filter_class(request.QUERY_PARAMS, queryset=queryset)
+            return filter_class(request.QUERY_PARAMS, queryset=queryset).qs
 
         return queryset