D23875: KCoreDirLister: fix crash when creating new folders from kfilewidget

[David Faure]

dfaure resigned from this revision.

REPOSITORY
  R241 KIO

REVISION DETAIL
  https://phabricator.kde.org/D23875

To: ahmadsamir, #frameworks
Cc: dhaumann, kde-frameworks-devel, LeGast00n, GB_2, michaelh, ngraham, bruns