Make method private because it's used only internally

Remove transaction annotation since it was not being effective.

FEA: ItEr64S03BugFixing

navalplanner-webapp/src/main/java/org/navalplanner/web/planner/order/OrderPlanningModel.java

@@ -1583,8 +1583,7 @@ public abstract class OrderPlanningModel implements IOrderPlanningModel {
                     .getCriticalPathProgressByNumHours());
         }
 
-        @Transactional(readOnly=true)
-        public void update() {
+        private void update() {
             TaskGroup rootTask = planningState.getRootTask();
             updateCriticalPathProgress(rootTask);
         }