the number of partitions is > OLDMAXPARTITIONS. This is better
than silently truncating the label (don't want to silently throw
away partitions when using an old disklabel binary on a label with
> 8 partitions). From Enami Tsugutomo.
change these from bp->b_un.b_addr to bp->b_data, as well. This also
allows us more flexibility to experiment with other data buffer types
hung off of struct buf.
fvdl