D26868: Move newItem to private method in KConfigSourceGenerator

[Tomaz Canabrava]

tcanabrava added reviewers: ervin, dfaure.

REPOSITORY
  R237 KConfig

REVISION DETAIL
  https://phabricator.kde.org/D26868

To: tcanabrava, ervin, dfaure
Cc: kde-frameworks-devel, LeGast00n, GB_2, michaelh, ngraham, bruns