MEDIUM: stream: move the listener's pointer to the session

The listener is session-specific, move it there.
diff --git a/src/hlua.c b/src/hlua.c
index 4b56187..1a0b920 100644
--- a/src/hlua.c
+++ b/src/hlua.c
@@ -2133,7 +2133,7 @@
 	/* The stream dont have listener. The listener is used with real
 	 * proxies.
 	 */
-	socket->s->listener = NULL;
+	socket->s->sess->listener = NULL;
 
 	/* The flags are initialized to 0. Values are setted later. */
 	socket->s->flags = 0;