Fix rope protection handling and get rid of a global callback.

rope.lua

 local rope = {}
 
 -- Code by Mirko K. (modified by Temperest, Wulfsdad and kilbith) (License: GPL).
-minetest.register_on_punchnode(function(pos, oldnode, digger)
-	if oldnode.name == "xdecor:rope" then
-		rope:remove(pos, oldnode, digger, "xdecor:rope")
-	end
-end)
-
 function rope.place(itemstack, placer, pointed_thing)
 	if pointed_thing.type == "node" then
 		local pos = pointed_thing.above
@@ -27,7 +21,7 @@ function rope.place(itemstack, placer, pointed_thing)
 	return itemstack
 end
 
-function rope:remove(pos, oldnode, digger, rope_name)
+function rope.remove(pos, oldnode, digger, rope_name)
 	local num = 0
 	local below = {x=pos.x, y=pos.y, z=pos.z}
 	local digger_inv = digger:get_inventory()
@@ -52,5 +46,12 @@ xdecor.register("rope", {
 	inventory_image = "xdecor_rope_inv.png",
 	wield_image = "xdecor_rope_inv.png",
 	selection_box = xdecor.pixelbox(8, {{3, 0, 3, 2, 8, 2}}),
-	on_place = rope.place
+	on_place = rope.place,
+	on_punch = function(pos, node, puncher, pointed_thing)
+		local player_name = puncher:get_player_name()
+		if not minetest.is_protected(pos, player_name) or
+			minetest.get_player_privs(player_name).protection_bypass then
+			rope.remove(pos, node, puncher, "xdecor:rope")
+		end
+	end
 })