minor: better error message, remove unused code

SVN: 15856

datastore_server/source/java/ch/systemsx/cisd/openbis/dss/generic/server/plugins/standard/AbstractArchiverProcessingPlugin.java

@@ -120,7 +120,9 @@ public abstract class AbstractArchiverProcessingPlugin extends AbstractDatastore
                                 unarchive(dataset);
                             } catch (UserFailureException ex)
                             {
-                                return Status.createError(ex.getMessage());
+                                return Status
+                                        .createError(ex.getMessage() == null ? "unknown reason"
+                                                : ex.getMessage());
                             }
                             return Status.OK;
                         }

datastore_server/source/java/ch/systemsx/cisd/openbis/dss/generic/shared/QueueingDataSetStatusUpdaterService.java

@@ -22,7 +22,6 @@ import java.util.List;
 import org.apache.log4j.Logger;
 import org.springframework.remoting.RemoteAccessException;
 
-import ch.rinn.restrictions.Private;
 import ch.systemsx.cisd.base.exceptions.InterruptedExceptionUnchecked;
 import ch.systemsx.cisd.common.TimingParameters;
 import ch.systemsx.cisd.common.collections.CollectionUtils;
@@ -60,9 +59,6 @@ public class QueueingDataSetStatusUpdaterService
 
     private static final int INITIAL_RECORD_SIZE = 128;
 
-    @Private
-    final static String UPDATER_PREFIX = ".UPDATER_";
-
     private static IExtendedBlockingQueue<DataSetCodesWithStatus> queue = null;
 
     private static ICloseable queueCloseableOrNull = null;