title: Symfony child entity only being validated as Type, skipping it's own validation
body: <p>I'm using the Symfony Validator on it's own, without the forms component. </p>
  
  <p>I have an entity which contains a child entity, currently I can validate that that field is an instance of the child entity, but I need it to also validate the child for it's constraints. </p>
  
  <pre><code>#validation.yml
  # This is the entity I'm validating against, it checks the type but doesn't then validate 
  # it against the child entity below. 
  Greg\PropertyBundle\Entity\Property:
      properties:
          property_id:
              - NotBlank: ~
              - Type:
                  type: string
          addresses:
              - All:
                  - Type:
                      type: Greg\PropertyBundle\Entity\Address
  
  # child entity
  Greg\PropertyBundle\Entity\Address:
      properties:
          city:
              - NotBlank: ~
              - Type:
                  type: string
  </code></pre>
  
  <p>To call the validator I'm passing it in with DI to one of my services and doing this:</p>
  
  <pre><code>// Validate the data
  $errorList = $this-&gt;validator-&gt;validate($data);
  </code></pre>
  
  <p>I have also tried it by passing in the following flags:</p>
  
  <pre><code>$errorList = $this-&gt;validator-&gt;validate($data, null, true, true);
  </code></pre>