dmabuf: Don't crash clients by sending version inappropriate events

We need to make sure the client bound dmabuf with a high enough
version to receive modifier events before sending them or the
client will crash.

Signed-off-by: Derek Foreman <derekf@osg.samsung.com>
Reviewed-by: Daniel Stone <daniels@collabora.com>

libweston/linux-dmabuf.c

@@ -483,6 +483,8 @@ bind_linux_dmabuf(struct wl_client *client,
 	wl_resource_set_implementation(resource, &linux_dmabuf_implementation,
 				       compositor, NULL);
 
+	if (version < ZWP_LINUX_DMABUF_V1_MODIFIER_SINCE_VERSION)
+		return;
 	/*
 	 * Use EGL_EXT_image_dma_buf_import_modifiers to query and advertise
 	 * format/modifier codes.