buildsystem: use /usr/bin/python3 in scripts

tools/fixlecode.py

@@ -1,10 +1,9 @@
-#!/usr/bin/env python
+#!/usr/bin/env python3
 # -*- coding: utf-8 -*-
 
 # SPDX-License-Identifier: GPL-2.0
 # Copyright (C) 2019-present Team LibreELEC (https://libreelec.tv)
 
-from __future__ import print_function
 import os
 import sys
 import re