Added missing Umbala Dungeon mob reference in conf files for pre-RE servers.

git-svn-id: https://svn.code.sf.net/p/rathena/svn/trunk@16457 54d463be-8e91-2dee-dedb-b68131a5f0ec

npc/pre-re/scripts_monsters.conf

@@ -67,6 +67,7 @@ npc: npc/pre-re/mobs/dungeons/tha_t.txt
 npc: npc/pre-re/mobs/dungeons/thor_v.txt
 npc: npc/pre-re/mobs/dungeons/treasure.txt
 npc: npc/pre-re/mobs/dungeons/tur_dun.txt
+npc: npc/pre-re/mobs/dungeons/un_dun.txt
 npc: npc/pre-re/mobs/dungeons/xmas_dun.txt
 npc: npc/pre-re/mobs/dungeons/yggdrasil.txt