Git commits in Moodle 3.5.5 by eWallah

commit 6e81e436bf691af2d621296761e96b3aada33bf7
Author: eWallah <info@eWallah.net>
Date:   Tue, 22 Jan 2019 22:47:14 +0800
Tag:    v3.5.5

MDL-63168 core_message: fix failures in migrate_message_data task.

commit b50e1b24505afa18320b75ea2ac25b2761230368
Author: eWallah <info@eWallah.net>
Date:   Tue, 22 Jan 2019 18:35:36 +0800
Tag:    v3.5.5

MDL-64633 behat: fix FormatterNotFoundException when updating steps.