Git commits in Moodle 3.7.3 by Mark Johnson

commit 6bdfddc463a39c363ed1d985fb395d986118c308
Author: Mark Johnson <mark.johnson@open.ac.uk>
Date:   Thu, 11 Apr 2019 16:02:31 +0800
Tag:    v3.7.3

MDL-65335 auth: Make oauth2 enabled check more efficient