[mcl_experience] fix warnings

mods/HUD/mcl_experience/init.lua

@@ -1,5 +1,11 @@
 local S = minetest.get_translator("mcl_experience")
+
 mcl_experience = {}
+
+local vector = vector
+local math = math
+local string = string
+
 local pool = {}
 local registered_nodes
 local max_xp = 2^31-1
@@ -262,7 +268,6 @@ function mcl_experience.add_experience(player, experience)
 	if #final_candidates > 0 then
 		local can = final_candidates[math.random(#final_candidates)]
 		local stack, list, index, wear = can.stack, can.list, can.index, can.wear
-		local unbreaking_level = mcl_enchanting.get_enchantment(stack, "unbreaking")
 		local uses = mcl_util.calculate_durability(stack)
 		local multiplier = 2 * 65535 / uses
 		local repair = experience * multiplier
@@ -329,14 +334,12 @@ minetest.register_on_dieplayer(function(player)
 	mcl_experience.throw_experience(player:get_pos(), xp_amount)
 end)
 
-
-local name
 local collector, pos, pos2
 local direction, distance, player_velocity, goal
 local currentvel, acceleration, multiplier, velocity
 local node, vel, def
 local is_moving, is_slippery, slippery, slip_factor
-local size, data
+local size
 local function xp_step(self, dtime)
 	--if item set to be collected then only execute go to player
 	if self.collected == true then