[HEADSUP] changes to cam_get_device() and cam_open_device()

[Matthew Jacob]

  You might add a comment about why nfoo0 is a special case. Other than 
that, looks ok to me.
> Matthew, thanks a lot!
> Here is a new variant of the camlib.c patch:
> http://people.freebsd.org/~avg/cam_get_device.2.diff
>
> I tried to preserve 'n' behavior (and added 'e'), but in a little bit more
> elaborate fashion.
> Instead of just checking for a leading 'n' I try to check for a known "non-rewind"
> peripheral name between the 'n' and unit number.
> I am aware only of sa(4) driver with such a feature at present.
>