Author: David Woloszyn
MDL-86724 hub: Registration collects disk usage data
http://git.moodle.org/gw?p=moodle.git;a=commit;h=bf019a00ac68e3ed9a62846d72a0fe498b69e7be
http://github.com/moodle/moodle/commit/bf019a00ac68e3ed9a62846d72a0fe498b69e7be
+ 5.2 en [diskusagesize,core_hub]