Fix leak

src/hb-ot-shape.cc

diff --git a/src/hb-ot-shape.cc b/src/hb-ot-shape.cc
index e04e700..7831f90 100644
--- a/src/hb-ot-shape.cc
+++ b/src/hb-ot-shape.cc
@@ -203,6 +203,8 @@
 _hb_ot_shaper_shape_plan_data_destroy (hb_ot_shaper_shape_plan_data_t *data)
 {
   data->map.finish ();
+
+  free (data);
 }