Merge pull request #4846 from ghalliday/issue10048

HPCC-10048 Fix uninitialised variable in XREFDirectoryBuilder::getDirectory

Reviewed-By: Richard Chapman <rchapman@hpccsystems.com>
HPCC-10046 Optimize aggregate on single row datasets

Signed-off-by: Gavin Halliday <gavin.halliday@lexisnexis.com>