Avoid cloning Resource in FSAppAttempt#updateDemand

public void updateDemand() {
    demand = Resources.createResource(0);
    // Demand is current consumption plus outstanding requests
    Resources.addTo(demand, app.getCurrentConsumption());

    // Add up outstanding resource requests
    synchronized (app) {
      for (Priority p : app.getPriorities()) {
        for (ResourceRequest r : app.getResourceRequests(p).values()) {
          Resource total = Resources.multiply(r.getCapability(), r.getNumContainers());
          Resources.addTo(demand, total);
        }
      }
    }
  }

public static Resource multiply(Resource lhs, double by) {
    return multiplyTo(clone(lhs), by);
}