Bug #1448: Fix issue reattaching the work report before removing

This allows to navigate the work report lines without problems.

FEA: ItEr76S04BugFixing

libreplan-webapp/src/main/java/org/libreplan/web/workreports/WorkReportModel.java

@@ -412,6 +412,7 @@ public class WorkReportModel extends IntegrationEntityModel implements
     public void remove(WorkReport workReport) {
         //before deleting the report, update OrderElement.SumChargedHours
         try {
+            workReportDAO.reattach(workReport);
             sumChargedEffortDAO
                     .updateRelatedSumChargedEffortWithDeletedWorkReportLineSet(workReport
                             .getWorkReportLines());