[SCSI] libfc: fix WARNING from fc_seq_start_next on closed exchanges

We saw periodic messages like:

WARNING: at drivers/scsi/libfc/fc_exch.c:825 fc_seq_start_next+0x30/0x4b

This was due to trying to allocate a sequence in a request handler
when the exchange had been reset.

Delete the WARN_ON.
Signed-off-by: Joe Eykholt <jeykholt@cisco.com>
Signed-off-by: Robert Love <robert.w.love@intel.com>
Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>
Signed-off-by: James Bottomley <James.Bottomley@suse.de>

drivers/scsi/libfc/fc_exch.c

@@ -822,7 +822,6 @@ struct fc_seq *fc_seq_start_next(struct fc_seq *sp)
 	struct fc_exch *ep = fc_seq_exch(sp);
 
 	spin_lock_bh(&ep->ex_lock);
-	WARN_ON((ep->esb_stat & ESB_ST_COMPLETE) != 0);
 	sp = fc_seq_start_next_locked(sp);
 	spin_unlock_bh(&ep->ex_lock);