Auto SCSI CD boot problem solved

[Matthew Dillon]

    Ok, I finally dug up a SCSI CDROM Drive and figured out the issue.
    For those who don't remember:

    * The DragonFly ISO boots on a SCSI CDROM Drive but is unable to mount
      root automatically.

    * Specifying 'cd9660:cd0c' at the mountroot prompt succeeds.

    The issue turns out to be that the SCSI driver is stricter about the
    device name.  It will allow 'cd0c', but will not allow 'cd0a'.  The
    ATA driver on the otherhand will accept both 'acd0c' and 'acd0a'.

    The kernel auto-mount was trying: cd0a, acd0a, cd1a, acd1a, and thus
    saw the ATA CD's but not the SCSI CD's.

    I am doing some final testing on the change and will commit the fix
    tonight.

						-Matt