UFS2 commit.
These bits in essence made any instance of "softupdates expected
corrution", (ie blocks marked allocated but not referenced by an
inode etc) result in a exit value for fsck_ffs of 2.
2 is part of the magic and appearantly undocumented protocol between
fsck_FOO and fsck and means "dump into single user mode ASAP.
Sponsored by: DARPA & NAI Labs.