(show_disk, show_point): If several filesystems are

(show_disk, show_point): If several filesystems are
mounted on the same mount point, prefer the last one, not the first.
Problem reported by Christian Jones in
<http://mail.gnu.org/archive/html/bug-coreutils/2004-04/msg00200.html>.
(show_disk): Remove unused statp arg.  Return bool, not int.
(show_point): Rewrite to avoid gotos.  Use the same algorithm
for lofs and dummies for each pass through the mount table,
rather than subtly different algorithms (which are probably
inadvertent).