Preen and SunOS 4.0

[Alexander Dupuy]

One other problem which I noticed with our Sun-2s running 4.0: if you have
/usr mounted r/w and the pass # is not 1 (we had it as 2, from
suninstall), fsck will run the check as a child.  If there is repairable
damage on /usr (at this point a mounted filesystem) the child will return
4 to indicate that a reboot should be done.  But the parent will return 8
if any of its children return non-zero status, causing rc.boot to fail on
the autoboot.

The fix is for fsck to |-or it's childrens status together, rather than
returning 8 if any are non-zero.

The workaround is to make sure that any filesystems mounted when fsck -p
runs are checked in pass 1.

@alex