LMS-769 workaround for re-registering DSS after openBIS shutdown.

SVN: 10282

datastore_server/source/java/ch/systemsx/cisd/openbis/dss/generic/server/EncapsulatedOpenBISService.java

@@ -246,6 +246,7 @@ public final class EncapsulatedOpenBISService implements IEncapsulatedOpenBISSer
 
     synchronized public ExternalDataPE tryGetDataSet(String sToken, String dataSetCode) throws UserFailureException
     {
+        checkSessionToken();
         return service.tryGetDataSet(sToken, dataSetCode);
     }