HPCC-9026 Pull distributor restart issues

Effects Distribute Merge and Global Hash Aggregate inside LOOP

Signed-off-by: Jake Smith <jake.smith@lexisnexis.com>
Merge pull request #4163 from jakesmith/hpcc-9026

HPCC-9026 Pull distributor restart issues

Reviewed-By: Richard Chapman <rchapman@hpccsystems.com>