Clean module registration
Summary: Registration of other modules in the scheduler might be executed more than once. I am not sure whether this the source of problems difficult to reproduce, but even if not, it's cleaner like this.
Reviewers: mutlaqja, TallFurryMan
Reviewed By: mutlaqja
Subscribers: kde-edu
Tags: KDE Edu
Differential Revision: https://phabricator.kde.org/D20365