Change answer <-> response matching in capa.get_submission_metadata

common/lib/xmodule/xmodule/capa_base.py

@@ -1186,9 +1186,8 @@ class CapaMixin(CapaFields):
 
             answer_response = None
             for response, responder in self.lcp.responders.iteritems():
-                for other_input_id in self.lcp.responder_answers[response]:
-                    if other_input_id == input_id:
-                        answer_response = responder
+                if input_id in responder.answer_ids:
+                    answer_response = responder
 
             if answer_response is None:
                 log.warning('Answer responder could not be found for input_id %s.', input_id)