When the local sync target is just a drive letter (e.g. "X:\"), neither
the display of the sync status via file icon overlay, nor the creation of a
share link works. In the latter case no pop-up comes up and no server
request is done.
QDir::cleanPath() usually removes trailing slashes, but not if the path to
be cleaned is just "X:\". In that case the trailing slash is kept. This
commit accounts for that exception.
Christian Burger