message: Fix ClusterTree::ConstIterator copy constructor
diff: @@ -1305,6 +1305,7 @@ ClusterTree::ConstIterator::ConstIterator(const ClusterTree& t, Key key)
  : m_tree(t)
  , m_leaf(t.get_alloc(), t)
  , m_state(m_leaf)
  + , m_instance_version(t.get_instance_version())
  , m_key(key)
  {
  }
  