fix SingleDuel::LeaveGame

Author: mercury233

gframe/single_duel.cpp

@@ -172,6 +172,7 @@ void SingleDuel::LeaveGame(DuelPlayer* dp) {
 				wbuf[0] = MSG_WIN;
 				wbuf[1] = 1 - dp->type;
 				wbuf[2] = 0x4;
+				duel_stage = DUEL_STAGE_END;
 				NetServer::SendBufferToPlayer(players[0], STOC_GAME_MSG, wbuf, 3);
 				NetServer::ReSendToPlayer(players[1]);
 				for(auto oit = observers.begin(); oit != observers.end(); ++oit)