Fix 'camcontrol inquiry'. The inquiry data structure changes (increased to
256 bytes) caused it to break on many devices.

The SCSI spec says that for commands with 8-bit length fields, a value of 0
means 256 bytes. As it turns out, many devices don't deal with that
properly. Some interpret the 0 as 0, and return no data. Others return
more than 256 bytes of data, and cause an overrun.

The fix is to tell the device we've only allocated SHORT_INQUIRY_LENGTH (36
bytes) of inquiry data, instead of sizeof(struct scsi_inquiry_data).

camcontrol.c: Change inq_len in the call to scsi_inquiry() to

			SHORT_INQUIRY_LENGTH, and add a long comment
			explaining the reason for the change.

scsi_all.h: Add a comment above the definitinon of

			SHORT_INQUIRY_LENGTH alerting people that it is
			both the initial probe inquiry length, and the
			minimum amount of data needed for scsi_print_inquiry()
			to function.

scsi_all.c: Add a comment about SHORT_INQUIRY_LENGTH being the

			minimum amount of data needed for
			scsi_print_inquiry() to function.

Reviewed by: gibbs
Approved by: jkh
Reported by: "John W. DeBoskey" <jwd@unx.sas.com>