"gio mount" doesn't print anything in case of success, however "gio mount -d"
prints "Mounted [id] at [mount_path]", which is inconsistent. It might probably
make sense for fstab volumes, but "gio mount -d" now support UUIDs which are
heavily used for daemon mounts and I think that it is not wise to print
"/run/user/$UID/gvfs" mount paths. The mount path can be still found over
"gio mount -l". Let's remove this message to make it more consistent.