message: fix for sum op case
diff: @@ -9086,7 +9086,8 @@ double Mesh::AggregateError(const Array<double> &elem_error,
  const int *fine, int nfine, int op)
  {
  double error = elem_error[fine[0]];
  - for (int i = 0; i < nfine; i++)
  +
  + for (int i = 1; i < nfine; i++)
  {
  MFEM_VERIFY(fine[i] < elem_error.Size(), "");
  