D13917: Use non deprecated fastInsert in renameDialog

[David Faure]

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

REPOSITORY
  R241 KIO

REVISION DETAIL
  https://phabricator.kde.org/D13917

To: jtamate, dfaure, #frameworks
Cc: kde-frameworks-devel, michaelh, ngraham, bruns