#4 mfsinfo segfaults

[Stephen M. Moraco]

run mfsinfo against two drive pair, nodma kernel both
drives hdx=bswap. In my case I'm seeing Zone Map
primary and secondary corrupt and checksum bad
messages after which i get the segfault.

I figure the segfault part is a bug. I figure that the
zone map stuff is the not-so-good state of my drives :(