HPCC-8605 - Ensure log files are recorded to the workunit

If the log rollover to a new log file (at midnighg) during
a Thor job, only the initial log was recorded in the wuid.
Update at end of each subgraph.

Signed-off-by: Jake Smith <jake.smith@lexisnexis.com>
Merge pull request #3872 from jakesmith/hpcc-8605

HPCC-8605 - Ensure log files are recorded to the workunit

Reviewed-By: Richard Chapman <rchapman@hpccsystems.com>