Not only is shg's answer valid, it's technically more correct. "What would the other entity (spirit being) say if I asked him, it this is the door that leads to heaven?" assumes that the two entities have knowledge of each other's habits, which is not necessarily guaranteed by the construct of the problem.
Two truths = correct classification of the door. Two (offsetting) lies = also correct classification of the door.
Plus, with shg's answer, you could remove one of the statues entirely and, armed only with the knowledge that the statue either *always* lies or *always* tells the truth, you could pick the right door.