HPCC-11756 Rebuild persist if input persist is newer

Signed-off-by: Gavin Halliday <gavin.halliday@lexisnexis.com>
Merge pull request #6217 from ghalliday/issue11756b

HPCC-11756 Rebuild persist if input persist is newer

Reviewed-By: Richard Chapman <rchapman@hpccsystems.com>