D5970: Fix KSNIs being unable to register service under flatpak

[Jan Grulich]

jgrulich accepted this revision.
This revision is now accepted and ready to land.

REPOSITORY
  R289 KNotifications

BRANCH
  master

REVISION DETAIL
  https://phabricator.kde.org/D5970

To: davidedmundson, #frameworks, jgrulich
Cc: jgrulich