tools/virtio: fix build for 3.8

Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
diff --git a/tools/virtio/virtio_test.c b/tools/virtio/virtio_test.c
index fcc9aa2..faf3f0c 100644
--- a/tools/virtio/virtio_test.c
+++ b/tools/virtio/virtio_test.c
@@ -92,7 +92,8 @@
 	assert(r >= 0);
 	memset(info->ring, 0, vring_size(num, 4096));
 	vring_init(&info->vring, num, info->ring, 4096);
-	info->vq = vring_new_virtqueue(info->vring.num, 4096, &dev->vdev,
+	info->vq = vring_new_virtqueue(info->idx,
+				       info->vring.num, 4096, &dev->vdev,
 				       true, info->ring,
 				       vq_notify, vq_callback, "test");
 	assert(info->vq);