allow pvp in arenas

nopvp.lua

@@ -15,6 +15,10 @@ minetest.register_on_punchplayer(function(player, hitter, time_from_last_punch,
 		return false
 	end
 
+	if minetest.check_player_privs(player_name, {arena=true}) then
+		return false
+	end
+
 	if not minetest.check_player_privs(player_name, {pvp=true}) then
 		return true
 	end