GetFile generates a failed event if a checksum pillar is present

Currently a IdentifyPillarsForGetFile will generate a 'Request-Not-Understood' response, which will cause a ComponentFailedEvent to be generated, which again will generate a OperationFailed event.

As this is a good case, the operation should just complete successfully. More generally, should a getFile complete with a successful 'Complete' event, if only one pillar is successfull?