message: Fix replication of null timestamps in list
diff: @@ -524,8 +524,13 @@ void Lst<Binary>::insert_repl(Replication* repl, size_t ndx, BinaryData value)
  template <>
  void Lst<Timestamp>::insert_repl(Replication* repl, size_t ndx, Timestamp value)
  {
  + if (value.is_null()) {
  + repl->list_insert_null(*this, ndx);
  + }
  + else {
  repl->list_insert_timestamp(*this, ndx, value);
  }
  +}
  template <>
  void Lst<ObjKey>::insert_repl(Replication* repl, size_t ndx, ObjKey key)
  