tests: Handle screenshot done event in weston-test

Signed-off-by: Bryce Harrington <bryce@osg.samsung.com>
Reviewed-By: Derek Foreman <derekf@osg.samsung.com>
diff --git a/tests/weston-test-client-helper.h b/tests/weston-test-client-helper.h
index 2564044..0ff2877 100644
--- a/tests/weston-test-client-helper.h
+++ b/tests/weston-test-client-helper.h
@@ -64,6 +64,7 @@
 	int pointer_x;
 	int pointer_y;
 	uint32_t n_egl_buffers;
+	int buffer_copy_done;
 };
 
 struct input {