D8946: Avoid unnecessary 'dataChanged' signal

[Franck Arrecot]

franckarrecot added a dependent revision: D8450: User can now hide an entire 
places group from KFilePlacesView.

REPOSITORY
  R241 KIO

REVISION DETAIL
  https://phabricator.kde.org/D8946

To: renatoo, dfaure
Cc: ngraham, #frameworks