D10450: Generate a custom target in kcoreaddons_desktop_to_json

[Tobias C . Berner]

tcberner added reviewers: bshah, dfaure.

REPOSITORY
  R244 KCoreAddons

REVISION DETAIL
  https://phabricator.kde.org/D10450

To: tcberner, #freebsd, mpyne, bshah, dfaure
Cc: #frameworks, michaelh