Git commits in Moodle 3.1.8 by Simey Lameze

commit 39aacd1dfe8138654184bc98bcfc398508d60e89
Author: Simey Lameze <simey@moodle.com>
Date:   Tue, 15 Aug 2017 09:49:56 +0800
Tag:    v3.1.8

MDL-59776 core_calendar: unit tests of module events deletion

commit bc312c648a34efb66acc3a19f5da4884d1d8729f
Author: Simey Lameze <simey@moodle.com>
Date:   Wed, 09 Aug 2017 15:22:07 +0800
Tag:    v3.1.8

MDL-59776 core_calendar: prevent deletion of module events