[SCSI] Fix command result state propagation

We're seeing a case where the contents of scmd->result isn't being reset after
a SCSI command encounters an error, is resubmitted, times out and then gets
handled.  The error handler acts on the stale result of the previous error
instead of the timeout.  Fix this by properly zeroing the scmd->status before
the command is resubmitted.

Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>
diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c
index 7fa54fe..9db097a 100644
--- a/drivers/scsi/scsi_lib.c
+++ b/drivers/scsi/scsi_lib.c
@@ -137,6 +137,7 @@
 	 * lock such that the kblockd_schedule_work() call happens
 	 * before blk_cleanup_queue() finishes.
 	 */
+	cmd->result = 0;
 	spin_lock_irqsave(q->queue_lock, flags);
 	blk_requeue_request(q, cmd->request);
 	kblockd_schedule_work(q, &device->requeue_work);