[repacker] add missing fini for parents vector.
diff --git a/src/hb-repacker.hh b/src/hb-repacker.hh
index 1e8f491..df4efa8 100644
--- a/src/hb-repacker.hh
+++ b/src/hb-repacker.hh
@@ -46,7 +46,10 @@
         end (0),
         priority(0) {}
 
-    void fini () { obj.fini (); }
+    void fini () {
+      obj.fini ();
+      parents.fini ();
+    }
 
     hb_serialize_context_t::object_t obj;
     int64_t distance;