Fix a problem reported by bde: setting SCSI_DELAY to 0 doesn't work. Now,
when the user sets SCSI_DELAY to 0, we re-set it to the minimum allowable
bus settle delay (100ms).
Fix a potential panic in xptfinishconfigfunc() if the CCB passed in is
NULL. Reported by, I think, Nicolas Souchu. Fix a memory leak in the same
function (we created a path, but didn't free it) by allocating the getdev
CCB and path on the stack.
Reviewed by: gibbs
only. Previously, if the device was chmoded 644, someone could open it
with the O_RDONLY flag and issue any ioctl to the device.
Reviewed by: imp, gibbs
