let auto forward mode get result_code

src/handle_user_cmd.cxx

@@ -347,8 +347,8 @@ void raft_server::auto_fwd_resp_handler( ptr<cmd_result<ptr<buffer>>> presult,
             resp_ctx = resp->get_ctx();
             presult->accept();
         }
+        presult->set_result_code(resp->get_result_code());
     }
-
     presult->set_result(resp_ctx, perr);
     auto_fwd_release_rpc_cli(cur_pkg, rpc_cli);
 }