Full revert of r12402, could be the cause of mob respawn problems (followup to r12512)

git-svn-id: https://svn.code.sf.net/p/rathena/svn/trunk@12534 54d463be-8e91-2dee-dedb-b68131a5f0ec

src/map/mob.c

@@ -946,13 +946,6 @@ int mob_spawn (struct mob_data *md)
 		md->bl.x = md->spawn->x;
 		md->bl.y = md->spawn->y;
 
-		if( map[md->spawn->m].users == 0 && md->spawn->state.dynamic )
-		{// cache the mob instead of spawning it
-			//FIXME: deleting 'md' is a potentially dangerous operation
-			unit_free(&md->bl,0);
-			return 0;
-		}
-
 		if ((md->bl.x == 0 && md->bl.y == 0) || md->spawn->xs || md->spawn->ys)
 		{	//Monster can be spawned on an area.
 			if (!map_search_freecell(&md->bl, -1,