D27207: Use a less convoluted way to check if it's in flatpak

[Jan Grulich]

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

REPOSITORY
  R271 KDBusAddons

BRANCH
  master

REVISION DETAIL
  https://phabricator.kde.org/D27207

To: apol, jgrulich
Cc: kde-frameworks-devel, LeGast00n, cblack, GB_2, michaelh, ngraham, bruns