Git commits in Moodle 3.7.x by Claude Vervoort

commit 7a81ee607f3a80aa24c769cfb92a4310e33687c0
Author: Claude Vervoort <claude.vervoort@cengage.com>
Date:   Thu, 24 Oct 2019 22:49:47 +0800
Tag:    v3.7.4

MDL-66708 lti adv: fix check for key in config

commit 25ad68293c03772422ea6156de6827c6b5964dc5
Author: Claude Vervoort <claude.vervoort@cengage.com>
Date:   Thu, 31 Jan 2019 05:13:03 +0800
Tag:    v3.7.0-beta

MDL-64730 LTI Adv: do not ignore 0 score

commit 9d6f9d1d47df914b92323ee7d478e23393907cfb
Author: Claude Vervoort <claude.vervoort@cengage.com>
Date:   Mon, 10 Dec 2018 23:26:12 +0800
Tag:    v3.7.0-beta

MDL-64357 ltiservice_gradebookservices: fix cleanup deleting lineitems