HPCC-10443 - Regression introduced by hpcc-9577, possible crash

Use of a method that used to return a reference to a boolean
to return non-reference causes invalid memory access.
The reference used to be stored as a reference member in a class.

Signed-off-by: Jake Smith <jake.smith@lexisnexis.com>
Merge pull request #5160 from jakesmith/hpcc-10443

HPCC-10443 - Regression introduced by hpcc-9577, possible crash

Reviewed-by: Gavin Halliday <ghalliday@hpccsystems.com>