minor: remove unused class

SVN: 9648

openbis/source/java/ch/systemsx/cisd/openbis/generic/client/web/server/resultset/IFieldComparator.java

-package ch.systemsx.cisd.openbis.generic.client.web.server.resultset;
-
-import java.util.Comparator;
-
-/**
- * An {@link Comparator} extension which bases its sorting on a specified class field.
- * 
- * @author Christian Ribeaud
- */
-interface IFieldComparator<T> extends Comparator<T>
-{
-    /**
-     * Set the field name which determines the sorting.
-     * <p>
-     * Must be specified before comparison occurs.
-     * </p>
-     */
-    void setFieldName(final String fieldName);
-}
\ No newline at end of file