[master] Fix transformation-debug when jobIDs are provided

When job IDs are provided in transformation-debug, it is necessary to go through tasks and then get associated files, but files may have been used into another task, and then one should re-associate task and file.

Add a few changes to get the last line of output also for job stalled by watchdog, and print list of files when requesting tasks or jobs

Fix problem with error handling in popularity scan that was causing an exception...