because we forgot to pass 'true' as the human parameter on one of the
two calls to format_string.
Also, this is a worsening of quality; previously we would produce
16 (0x10)
to make it obvious which number was hex.
Fix these issues.
Reported-by: Eric Blake <eblake@redhat.com> Signed-off-by: Michael S. Tsirkin <mst@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com>