LMS-1165 fixing tests, checking null pointers

.../java/ch/systemsx/cisd/etlserver/BDSStorageProcessor.java

...ce/java/ch/systemsx/cisd/etlserver/DataStrategyStore.java

...ch/systemsx/cisd/etlserver/TransferredDataSetHandler.java

...h/systemsx/cisd/etlserver/imsb/HCSImageFileExtractor.java

...penbis/dss/generic/server/EncapsulatedOpenBISService.java

...sd/openbis/dss/generic/shared/dto/DataSetInformation.java

...a/ch/systemsx/cisd/etlserver/BDSStorageProcessorTest.java

...ava/ch/systemsx/cisd/etlserver/DataStrategyStoreTest.java

...ystemsx/cisd/etlserver/TransferredDataSetHandlerTest.java