When chown or chgrp is modifying the referent of a symlink,

When chown or chgrp is modifying the referent of a symlink,
use the chown(2) function, if possible.

(change_file_owner): Don't hard-code the
open/fchown/close kludge here.  Use `chown' instead.
The chown function works just fine on conforming systems.
Other systems now go through the new chown wrapper that
resorts to the old kludge.