Removed `party_skill_penalty` battle config, unused since r996 (bugreport:137).

git-svn-id: https://svn.code.sf.net/p/rathena/svn/trunk@15537 54d463be-8e91-2dee-dedb-b68131a5f0ec

src/map/battle.h

@@ -276,7 +276,6 @@ extern struct Battle_Config
 	int mob_changetarget_byskill;
 	int attack_direction_change;
 	int land_skill_limit;
-	int party_skill_penalty;
 	int monster_class_change_recover;
 	int produce_item_name_input;
 	int display_skill_fail;