Merge/Processing job file parentage fix

Original code brakes the parentage of files from Processing job when one of the job fails. 

This patch will do,
If one of processing job fails from the same job group, it will still set the parentage correctly.
If merge job fails within the same job group. the parentage won't be set the input files on the whole merge job group.
So robust merge can be still sported.
Dirk please review. basic unit test is added. But ops will do through test.