MEDIUM: session: use the pointer to the origin instead of s->si[0].end

When s->si[0].end was dereferenced as a connection or anything in
order to retrieve information about the originating session, we'll
now use sess->origin instead so that when we have to chain multiple
streams in HTTP/2, we'll keep accessing the same origin.
diff --git a/src/hlua.c b/src/hlua.c
index 363c09b..650051a 100644
--- a/src/hlua.c
+++ b/src/hlua.c
@@ -3505,7 +3505,7 @@
 	htxn = MAY_LJMP(hlua_checktxn(L, 1));
 	tos = MAY_LJMP(luaL_checkinteger(L, 2));
 
-	if ((cli_conn = objt_conn(htxn->s->si[0].end)) && conn_ctrl_ready(cli_conn))
+	if ((cli_conn = objt_conn(htxn->s->sess->origin)) && conn_ctrl_ready(cli_conn))
 		inet_set_tos(cli_conn->t.sock.fd, cli_conn->addr.from, tos);
 
 	return 0;
@@ -3522,7 +3522,7 @@
 	htxn = MAY_LJMP(hlua_checktxn(L, 1));
 	mark = MAY_LJMP(luaL_checkinteger(L, 2));
 
-	if ((cli_conn = objt_conn(htxn->s->si[0].end)) && conn_ctrl_ready(cli_conn))
+	if ((cli_conn = objt_conn(htxn->s->sess->origin)) && conn_ctrl_ready(cli_conn))
 		setsockopt(cli_conn->t.sock.fd, SOL_SOCKET, SO_MARK, &mark, sizeof(mark));
 #endif
 	return 0;