Fix arena start crash

Stair up in Yillkgur has a tile


git-svn-id: http://svn.net-core.org/repos/t-engine4@3888 51575b47-30f0-44d4-a5cc-537603b46e54

game/modules/tome/data/zones/arena/zone.lua

@@ -258,7 +258,7 @@ return {
 				return ranks[rank]
 			end,
 			updateScores = function(l)
-				local scores = world.arena.scores
+				local scores = world.arena.scores or {}
 				table.insert(scores, l)
 				table.sort(scores, function(a,b) return a.score > b.score end)
 				if #scores > 10 then table.remove(scores) end

game/modules/tome/data/zones/shertul-fortress/grids.lua

@@ -20,12 +20,10 @@
 load("/data/general/grids/basic.lua")
 load("/data/general/grids/fortress.lua")
 
-newEntity{
+newEntity{ base = "UP",
 	define_as = "LAKE_NUR",
 	name = "stair back to the lake of Nur",
 	display = '<', color_r=255, color_g=255, color_b=0,
-	notice = true,
-	always_remember = true,
 	change_level = 3, change_zone = "lake-nur", force_down = true,
 }