MDL-37974 code area: manual enrolment expiration - add option to suspend and fire event without deleting data

Previously, MDL-35063 added some options of what to do when an enrolment expires.
One existing option will fire an event, mark the enrolement suspended, and delete user data by removing roles.
This patch adds an option to fire event (and mark suspended) without removing roles or deleting data.
MDL-30775 get_course_contents: remove warnings when the section is empty
on demand release 2.5beta+
Ignore version.php in future commits
Ignore version.php in future commits
Merge branch 'master' of github.com:MorrisR2/moodle into MDL-37974-enrolment-expiration-suspend-no-remove-roles

Conflicts:
	course/externallib.php
	version.php