Scan with conjuncts but no materialized slots crashes Impalad

 select count(*) from tpch_parquet.lineitem where rand() = 10.0 

int HdfsScanner::WriteTemplateTuples(TupleRow* row, int num_tuples) {
  DCHECK_GE(num_tuples, 0);
  DCHECK_EQ(scan_node_->tuple_idx(), 0);
  DCHECK_EQ(conjunct_evals_->size(), 0); <<------
  if (num_tuples == 0 || template_tuple_ == NULL) return num_tuples;

  Tuple** row_tuple = reinterpret_cast<Tuple**>(row);
  for (int i = 0; i < num_tuples; ++i) row_tuple[i] = template_tuple_;
  return num_tuples;
}