Fix release 0.38.0

Replace `@@plpythonu@@` vars in old_versions

server/extension/old_versions/cdb_dataservices_server--0.7.2--0.7.1.sql

@@ -43,7 +43,7 @@ RETURNS json AS $$
       plpy.error(error_msg)
   finally:
       quota_service.increment_total_service_use()
-$$ LANGUAGE plpythonu;
+$$ LANGUAGE @@plpythonu@@;
 
 CREATE OR REPLACE FUNCTION cdb_dataservices_server.obs_get_segment_snapshot(
   username TEXT,
@@ -81,4 +81,4 @@ RETURNS json AS $$
       plpy.error(error_msg)
   finally:
       quota_service.increment_total_service_use()
-$$ LANGUAGE plpythonu;
+$$ LANGUAGE @@plpythonu@@;