backport of #2492 from tomchristie ref #1850: _closable_objects as an…

Sebastian Wozny · Sebastian Wozny · commit 131e99baefaa · 2015-08-31T13:32:13.000+02:00
diff --git a/rest_framework/response.py b/rest_framework/response.py
@@ -91,4 +91,5 @@ def __getstate__(self):
         for key in ('accepted_renderer', 'renderer_context', 'data'):
             if key in state:
                 del state[key]
+        state['_closable_objects'] = []
         return state
