MINOR: peers: Always access the stream-int via the conn-stream

To be able to move the stream-interface from the stream to the conn-stream,
all access to the SI is done via the conn-stream. This patch is limited to
the peers part.
diff --git a/src/peers.c b/src/peers.c
index 76a0917..8e7246d 100644
--- a/src/peers.c
+++ b/src/peers.c
@@ -3216,15 +3216,15 @@
 	}
 
 	/* applet is waiting for data */
-	si_cant_get(&s->si[0]);
+	si_cant_get(cs_si(s->csf));
 	appctx_wakeup(appctx);
 
 	/* initiate an outgoing connection */
 	s->target = peer_session_target(peer, s);
-	if (!sockaddr_alloc(&s->si[1].dst, &peer->addr, sizeof(peer->addr)))
+	if (!sockaddr_alloc(&(cs_si(s->csb)->dst), &peer->addr, sizeof(peer->addr)))
 		goto out_free_strm;
 	s->flags = SF_ASSIGNED|SF_ADDR_SET;
-	s->si[1].flags |= SI_FL_NOLINGER;
+	cs_si(s->csb)->flags |= SI_FL_NOLINGER;
 
 	s->do_log = NULL;
 	s->uniq_id = 0;