[5.0] Cleaned abort method and imported HttpException

Thanks @GrahamCampbell  !
```php
    /**
     * Throw an HttpException with the given data.
     *
     * @param  int     $code
     * @param  string  $message
     * @param  array   $headers
     * @return void
     *
     * @throws \Symfony\Component\HttpKernel\Exception\HttpException
     */