HPCC-9535 Rationalize Roxie topology info

Fix another regression in previous commit (empty aclName should be accepted).

Signed-off-by: Richard Chapman <rchapman@hpccsystems.com>
Merge pull request #4558 from richardkchapman/roxie-topology-regression2

HPCC-9535 Rationalize Roxie topology info

Reviewed-by: Gavin Halliday <ghalliday@hpccsystems.com>