Developer credits
Git commits in Moodle 2.6.7 by David Monllao
commit c9fa67f7cba63fc1191eba691569b11dd6736430 Author: David Monllao <davidm@moodle.com> Date: Mon, 01 Dec 2014 10:29:05 +0800 Tag: v2.6.7 MDL-48329 core_message: Checking that messaging system is enabled