use kcrash so we get drkonqi to pop up on crashes

Test Plan: - kill -SEGV `pidof systemsettings5` brings up drkonqi

Reviewers: mart, bshah, davidedmundson

Reviewed By: bshah, davidedmundson

Subscribers: davidedmundson, plasma-devel

Tags: #plasma

Differential Revision: https://phabricator.kde.org/D10175