ACE-3121: Workflow Admin Console: Cannot change priority for activiti

- Handled priority property for Task
   - Determine if DelegateTask also needs similar handling

git-svn-id: https://svn.alfresco.com/repos/alfresco-enterprise/alfresco/HEAD/root@88557 c4b6b30b-aa2e-2d43-bbcb-ca4b014f7261

source/java/org/alfresco/repo/workflow/activiti/properties/ActivitiPriorityPropertyHandler.java

@@ -65,6 +65,10 @@ public class ActivitiPriorityPropertyHandler extends ActivitiTaskPropertyHandler
         {
             task.setPriority(priority);
         }
+        else
+        {
+            throw getInvalidPropertyValueException(key, value);
+        }
 
         return DO_NOT_ADD;
     }