Merge "Changes needed for old python version"

src/opserver/opserver.py

@@ -139,7 +139,7 @@ def redis_query_start(host, port, redis_password, qid, inp, columns):
     if columns is not None:
         for col in columns:
             m = TableSchema(name = col.name, datatype = col.datatype, index = col.index, suffixes = col.suffixes)
-            col_list.append(m.__dict__)
+            col_list.append(m._asdict())
     query_metadata = {}
     query_metadata['enqueue_time'] = OpServerUtils.utc_timestamp_usec()
     redish.hset("QUERY:" + qid, 'query_metadata', json.dumps(query_metadata))