events for reordering content nodes are not processed correctly

I can easily demonstrate this on the feature/reorder branch of the hippo-repository project.

• Place a breakpoint in EventJournalProcessor#processEvents on the line #372

  if (!currentChanges.isEmpty())
  

• In AutoExportIntegrationTest#autoexport_reorder_within_module, remove all actions except for

  mix.orderBefore("m4-content2", "m3-content1");
  

If you also set a breakpoint in EventJournalProcessor#processEvent, you'll see that events are coming in, but that the result is apparently "skippable".