fix minor channels lua error

modules/game_console/console.lua

@@ -100,8 +100,8 @@ local function onCreatureSpeak(name, level, speaktype, message, channelId, creat
     if channel then
       Console.addText(message, speaktype, channel)
     else
-      -- server sent a message on a channel that we are not aware of, must leave it
-      g_game.leaveChannel(channelId)
+      -- server sent a message on a channel that is not open
+      warning('message in channel id ', channelId, ' which is unknown, this is a server bug, relogin if you want to see messages in this channel')
     end
   end
 end