ItEr60S04ValidacionEProbasFuncionaisItEr59S04: Move validation annotation from field to method.

Validation annotations on fields causes problems when the entity is a
proxy.

navalplanner-business/src/main/java/org/navalplanner/business/planner/entities/Task.java

@@ -85,9 +85,13 @@ public class Task extends TaskElement {
 
     private CalculatedValue calculatedValue = CalculatedValue.END_DATE;
 
-    @Valid
     private Set<ResourceAllocation<?>> resourceAllocations = new HashSet<ResourceAllocation<?>>();
 
+    @Valid
+    private Set<ResourceAllocation<?>> getResourceAlloations() {
+        return new HashSet<ResourceAllocation<?>>(resourceAllocations);
+    }
+
     @AfterCopy
     private void ifLimitingAllocationRemove() {
         if (isLimiting()) {