Help out old saves.

game/modules/tome/class/Game.lua

@@ -624,6 +624,10 @@ function _M:resizeMapViewport(w, h, x, y)
 	w = math.floor(w)
 	h = math.floor(h)
 
+	-- convert from older faulty versionsPg
+	if game.level.map and rawget(game.level.map, "display_x") == Map.display.x and rawget(game.level.map, "display_y") == Map.display_y then
+		game.level.map.display_x, game.level.map.display_y = nil, nil
+	end
 	Map.display_x = x
 	Map.display_y = y
 	Map.viewport.width = w