sethome: Replace deprecated function calls (#2724)

mods/sethome/init.lua

@@ -29,7 +29,8 @@ sethome.set = function(name, pos)
 	if not player or not pos then
 		return false
 	end
-	player:set_attribute("sethome:home", minetest.pos_to_string(pos))
+	local player_meta = player:get_meta()
+	player_meta:set_string("sethome:home", minetest.pos_to_string(pos))
 
 	-- remove `name` from the old storage file
 	if not homepos[name] then
@@ -51,7 +52,8 @@ end
 
 sethome.get = function(name)
 	local player = minetest.get_player_by_name(name)
-	local pos = minetest.string_to_pos(player:get_attribute("sethome:home"))
+	local player_meta = player:get_meta()
+	local pos = minetest.string_to_pos(player_meta:get_string("sethome:home"))
 	if pos then
 		return pos
 	end