SCSI: fix Suspend I/O block/unblock path

From: James.Smart@Emulex.Com

urther testing is showing that we are having some i/o threads
prematurely die with the following message: "rejecting I/O to device
being removed"
Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>

drivers/scsi/scsi_lib.c

@@ -1030,7 +1030,8 @@ static int scsi_prep_fn(struct request_queue *q, struct request *req)
 	} else if (req->flags & (REQ_CMD | REQ_BLOCK_PC)) {
 
 		if(unlikely(specials_only)) {
-			if(specials_only == SDEV_QUIESCE)
+			if(specials_only == SDEV_QUIESCE ||
+					specials_only == SDEV_BLOCK)
 				return BLKPREP_DEFER;
 			
 			printk(KERN_ERR "scsi%d (%d:%d): rejecting I/O to device being removed\n",