Git commits in Moodle 3.1.5 by Tony Butler

commit b20d56c357c863c6524fcdff4409574e6fe42b68
Author: Tony Butler <tonyjbutler@gmail.com>
Date:   Tue, 14 Feb 2017 01:24:20 +0800
Tag:    v3.1.5

MDL-56122 assignfeedback_editpdf: Add test assertions for pdf generation


commit 8e99e8c0146f3be8a6daa7148460aa68834449d0
Author: Tony Butler <tonyjbutler@gmail.com>
Date:   Wed, 08 Feb 2017 22:33:48 +0800
Tag:    v3.1.5

MDL-57801 core_filestorage: Delete temp file if disk space runs out


commit 131e69e29be7456cebdb2c1cdd3901707483aed1
Author: Tony Butler <tonyjbutler@gmail.com>
Date:   Sat, 28 Jan 2017 01:26:24 +0800
Tag:    v3.1.5

MDL-57801 core_filestorage: Verify hash of temp file before committing


commit 9e49655f16cbc080efa392746cf09cd24128b89b
Author: Tony Butler <tonyjbutler@gmail.com>
Date:   Thu, 19 Jan 2017 07:21:30 +0800
Tag:    v3.1.5

MDL-56122 assignfeedback_editpdf: Regenerate PDF & page images if blank