D8321: Only check for legacy system tray icons if we're going to make one

[Martin Flöser]

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

REPOSITORY
  R289 KNotifications

BRANCH
  master

REVISION DETAIL
  https://phabricator.kde.org/D8321

To: davidedmundson, #plasma, graesslin
Cc: plasma-devel, #frameworks, ZrenBot, progwolff, lesliezhai, ali-mohamed, 
jensreuterberg, abetts, sebas, apol, mart