D15739: [Places panel] Don't show Root by default

[Nathaniel Graham]

ngraham added a task: T8349: Improve Places panel usability and presentation.

REPOSITORY
  R241 KIO

REVISION DETAIL
  https://phabricator.kde.org/D15739

To: ngraham, #dolphin, #vdg
Cc: kde-frameworks-devel, michaelh, ngraham, bruns