Git commits in Moodle 3.6.0 by Guillermo Alvarez

commit e0dac0f4d7f6eb45b23c2eb4f21a584f4cb90b07
Author: Guillermo Alvarez <guillermo.alvarez@blackboard.com>
Date:   Sat, 25 Aug 2018 01:40:06 +0800
Tag:    v3.6.0-beta

MDL-63231 filepicker: Skype validation for null values