If you had a UFS2 FS that didn't have it's super block at SBLOCK_UFS2,
you'll end up corrupting your FS as the superblock is updated and written
to a different location...
makefs used to put the superblock at SBLOCK_UFS1 for UFS 2 FS's causing
this issue...
Reviewed by: silience from mckusick
MFC after: 1 week