title: Symfony2: query_builder breaks ordering of preferred_choices on EntityType field
body: <p>When passing <code>preferred_choices</code> into an <code>EntityType</code> of a form in Symfony 2.8.6, in combination with <code>query_builder</code> (see <a href="http://symfony.com/doc/current/reference/forms/types/entity.html#query-builder" rel="nofollow">http://symfony.com/doc/current/reference/forms/types/entity.html#query-builder</a>), the preferred choices are reordered according to <code>query_builder</code> :-(</p>