correct comment

SVN: 25172

screening/source/core-plugins/screening/1/dss/maintenance-tasks/imaging-db-clean-up/plugin.properties

 #
 # Maintenance task which does a database clean up by deleting all data sets deleted in application server. 
-# This task assumes that data source 'proteomics-db' has been defined. 
+# This task assumes that data source 'imaging-db' has been defined. 
 #
 class = ch.systemsx.cisd.openbis.dss.etl.DeleteFromImagingDBMaintenanceTask
 # specified in seconds. Here : every day