message: remove null pointer setting
diff: @@ -625,9 +625,7 @@ void AmgXSolver::SetMatrix(const HypreParMatrix &A, const bool update_mat)
  return SetMatrixMPITeams(A, loc_A, loc_I, loc_J, update_mat);
  }
  - // Set A_ptr to NULL
  // Free A_csr data from hypre_MergeDiagAndOffd method
  - A_ptr = NULL;
  hypre_CSRMatrixDestroy(A_csr);
  mfem_error("Unsupported MPI_GPU combination \n");
  