* Purpose : Add a new command onto a queue, adding REQUEST_SENSE to head.
* Params : queue - destination queue
* SCpnt - command to add
* head - add command to head of queue
* Returns : 0 on error, !0 on success
*/
* Purpose : Add a new command onto a queue, adding REQUEST_SENSE to head.
* Params : queue - destination queue
* SCpnt - command to add
* head - add command to head of queue
* Returns : 0 on error, !0 on success
*/