Make twig ExceptionController conformed with ExceptionListener

| Q             | A
| ------------- | ---
| Bug fix?      | yes
| New feature?  | no
| BC breaks?    | no
| Deprecations? | no
| Tests pass?   | yes
| Fixed tickets | 
| License       | MIT
| Doc PR        | 

Parameter passed to exception controller from exception listener called ``format``, so variable ``_format`` in exception controller always takes default value.
https://github.com/symfony/symfony/blob/master/src/Symfony/Component/HttpKernel/EventListener/ExceptionListener.php#L120