D18030: Use the nicer K_PLUGIN_CLASS_WITH_JSON

[Aleix Pol Gonzalez]

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

REPOSITORY
  R495 Purpose Library

BRANCH
  master

REVISION DETAIL
  https://phabricator.kde.org/D18030

To: aacid, apol
Cc: kde-frameworks-devel, michaelh, ngraham, bruns