WC2 recall costs

It's fine to give this object also to remaining enemies.
(It's only unneccessary, as they are deleted afterwards.)
Though when side 4 is a human side it is useful.

data/campaigns/World_Conquest/lua/game_mechanics/recall.lua

@@ -11,7 +11,7 @@ end
 
 -- the implementation of the addons reduces recall cost mechanic.
 function wesnoth.wml_actions.wc2_set_recall_cost(cfg)
-	for i,u in ipairs(wesnoth.units.find_on_map { side = "1,2,3" }) do
+	for i,u in ipairs(wesnoth.units.find_on_map { side = "1,2,3,4" }) do
 		add_rc_object(u)
 	end
 end