changed to use libufs in revision 1.71. Without this, any write
failures in newfs were silently ignored.
Note that this will display a meaningless errno string in the case
of a short write as opposed to a write error, since bwrite()'s
return value does not allow the caller to determine if errno is
valid.
Reported by: Lukas Ertl <l.ertl@univie.ac.at>
Reviewed by: jmallett
Approved by: re (bmah)