Git commits in Moodle 3.1.3 by Henning Bostelmann

commit d558b6629b9338807b10459fd4fbec856ece7e0e
Author: Henning Bostelmann <henning.bostelmann@york.ac.uk>
Date:   Mon, 07 Nov 2016 01:38:26 +0800
Tag:    v3.1.3

MDL-55994 blog: Resolve warning messages in RSS feed generation