This update for plasma-browser-integration fixes the following issues:

- Don't supplement browsers (only for Leap 15.0)

Version update to 5.15.4:

* New bugfix release
* For more details please see: https://www.kde.org/announcements/plasma-5.15.4.php

Changes since 5.15.3:

* Update description before processing job state or error
* [Host] Add Message.sh

This update was imported from the openSUSE:Leap:15.0:Update update project.