Git commits in Moodle 3.6.x by David Herney

commit 97fd2fb575b396710c107a183391034c34cd34ce
Author: David Herney <davidherney@gmail.com>
Date:   Fri, 28 Sep 2018 07:40:46 +0800
Tag:    v3.6.0-beta

MDL-63323 course: Fixed wrong classes key in activity_navigation class