Job Scheduler

Change log message "SCHEDULER-947 setback(): order has been set back..." from warning to info. This warning doesn't give any information why the order was setback and may cause confusion if no setback is configured. It is better if the job implementation creates a warning when the order can no longer be set back. But the job implementation has to know when an order could not be set back anymore (because max setback has been reached). Therefore order.setback() needs to return a boolean value: true - the order was set back and will be processed again later false - the order could not be set back any more the common usage would be: if (!order.setback()) spooler_log.warn("Failed to find...");