SP-461 BIS-293 delete pre-staging directory on registration failure

...a/ch/systemsx/cisd/etlserver/registrator/DataSetFile.java

...ator/v1/AbstractOmniscientTopLevelDataSetRegistrator.java

.../etlserver/registrator/v1/DataSetRegistrationService.java

...sd/etlserver/registrator/v1/DataSetStorageRollbacker.java

...ator/v2/AbstractOmniscientTopLevelDataSetRegistrator.java

...trator/v2/AbstractProgrammableTopLevelDataSetHandler.java

.../etlserver/registrator/v2/DataSetRegistrationService.java

...sd/etlserver/registrator/v2/DataSetStorageRollbacker.java

...d/etlserver/registrator/DataSetStorageRollbackerTest.java