Fix crash in category comparison caused by incorrect filters

Authored by leinir on Mar 19 2019, 9:55 PM.

Description

Fix crash in category comparison caused by incorrect filters

Prior to this, we would crash when attempting to create our own
Applications Category instance in KNSBackend. We can now set the
and filters programmatically and no longer crash. The patch
durther outputs the entirety of the comparison conditions we're
using, for easier debuggings.

Differential Revision: https://phabricator.kde.org/D19880

Details