[SCSI] libsas, bsg: pass errors through correctly

Currently in BSG, errors returned in req->errors aren't passed back to
the calling programme (either via SG_IO or via read/write).  Fix this,
while preserving the SCSI convention of returning status in
req->errors.

Now update libsas to return errors correctly instead of to ignore
them.

Acked-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>

drivers/scsi/scsi_transport_sas.c

@@ -173,6 +173,7 @@ static void sas_smp_request(struct request_queue *q, struct Scsi_Host *shost,
 
 		handler = to_sas_internal(shost->transportt)->f->smp_handler;
 		ret = handler(shost, rphy, req);
+		req->errors = ret;
 
 		spin_lock_irq(q->queue_lock);