fix convert model bugs when convert dense_relative_transformer models

scripts/convert_t2t_to_fairseq.py

@@ -473,7 +473,7 @@ def convert_settings(settings):
     args['arch'] = 'relative_transformer'
 
   if use_relative_position_representation and use_dense:
-    args['arch'] = 'relative_dense_transformer'
+    args['arch'] = 'dense_relative_transformer'
   return argparse.Namespace(**args)