Git commits in Moodle x.x.x by Don Bowman

commit cf7b00b8cf20d6af829dfe76fb25b717c652c374
Author: Don Bowman <don@agilicus.com>
Date:   Thu, 14 May 2020 20:38:20 +0800
Tag:    v3.9.0-beta

MDL-68696 sessions: Fixed redis session handler for readonly