Git commits in Moodle 3.3.3 by Mark Nielsen

commit 2cbe55875408637d3a1b68b73c085809fa301ea2
Author: Mark Nielsen <mark@moodlerooms.com>
Date:   Fri, 01 Sep 2017 06:47:00 +0800
Tag:    v3.3.3

MDL-60001 core_files: Use local file for gzopen