[Bug #659] Fix bug

The problem is that the new container is newly created so it has no
task source.

FEA: ItEr61S05BugFixing

navalplanner-business/src/main/java/org/navalplanner/business/orders/entities/OrderLineGroup.java

@@ -88,7 +88,7 @@ public class OrderLineGroup extends OrderElement implements
 
         @Override
         protected void onChildRemovedAdditionalActions(OrderElement removedChild) {
-            if (removedChild.isScheduled()) {
+            if (removedChild.isScheduled() && getThis().isScheduled()) {
                 removeChildTask(removedChild);
             }
         }