fdisk/geom, AoE 5.2.1

[sah at softcardsystems.com (Sam)]

> Please be aware that we have _three_ I/O operations under 5.x and
> later:  BIO_READ, BIO_WRITE and BIO_DELETE.  Just return EOPNOTSUPP
> for BIO_DELETE.

I was filtering out anything but R/W before I got there.  Thanks for
the tip on EOPNOTSUPP, though.  I was returning EIO.

Sam