Git commits in Moodle 3.5.5 by Andreas Wagner

commit 9ebaea25f64bb7bb8c8708300fbfae602f48dac1
Author: Andreas Wagner <awagner@gmx.de>
Date:   Sun, 18 Nov 2018 23:34:05 +0800
Tag:    v3.5.5

MDL-60972 core_course: delete section files, when section is deleted.