finding an ffsv1 sb at 64k.
Also stop it playing with fs that have 'FS_FLAGS_UPDATED' set.
It certainly doesn't act on that falg, and my guess is that it is
playing the pre-ffsv2 fs.
Fixes part of PR kern/24809
I didn't have time to clean it up completely before my legal status
w.r.t. open source projects goes into limbo for a while. Other
developers are encouraged to play with the tool and get it into
release-worthy shape.
TODO list (see TODO file)
* verify it builds on -current, put it into release lists/etc. and src/sbin/Makefile
(built & tested on 1.6.1)
* make it ask questions before doing any work (confirm)
* create regression test suite (see discussions on tech-kern and
developers) and fix any bugs
* verify conversion to ANSI C didn't break anything
* port to UFS2