KFilePlacesView: Show busy indicator while (un)mounting a device
Both mounting (e.g. hard drive spinning up) and unmounting (e.g. syncing uncommited changes) could take some time. This provides better user feedback when the operation is taking some time to complete.
The busy indicator is shown even when the unmount wasn't triggered from this application but elsewhere (e.g. Device Notifier)
It also disables the "Unmount" action in the context menu during unmount and changes wording to "Unmounting…".
Edited by Kai Uwe Broulik