skip step if no job to process

[jrmbrgs]

If for the current step there is no job to process, go to next step
https://github.com/vpg/disturb/blob/beta/Library/Workflow/ManagerWorker.php#L196

Manager log :

2018-01-31 02:32:13 [INFO] Step createOptionPrestation ack SUCCESS
2018-01-31 02:32:13 [INFO] Id jb-ad_1 is 'STARTED'
2018-01-31 02:32:13 [INFO] Workflow jb-ad_1 - Current Step status : SUCCESS
2018-01-31 02:32:13 [INFO] Nb job(s) to run for createPrestationTransport : 0

Here the WF is stuck...