dm-mpath-rdac: don't stomp on a requests transfer bit

Without this, we get qla2xxx complaining about "ISP System Error".

What's happening here is the firmware is detecting a Xfer-ready from the
storage when in fact the data-direction for a mode-select should be a
write (DATA_OUT).

The following patch fixes the problem (typo). Verified by Brian, as
well.
Signed-off-by: Andrew Vasquez <andrew.vasquez@qlogic.com>
Verified-by: Brian De Wolf <bldewolf@csupomona.edu>
Signed-off-by: Chandra Seetharaman <sekharan@us.ibm.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

drivers/md/dm-mpath-rdac.c

@@ -292,7 +292,7 @@ static struct request *get_rdac_req(struct rdac_handler *h,
 	rq->end_io_data = h;
 	rq->timeout = h->timeout;
 	rq->cmd_type = REQ_TYPE_BLOCK_PC;
-	rq->cmd_flags = REQ_FAILFAST | REQ_NOMERGE;
+	rq->cmd_flags |= REQ_FAILFAST | REQ_NOMERGE;
 	return rq;
 }