Call to a member function has() on a non-object in Helper/TemplateHelper.php on line 66

Just installed gush and got the following error:

```bash
PHP Fatal error:  Call to a member function has() on a non-object in phar:///usr/local/bin/gush/src/Helper/TemplateHelper.php on line 66
PHP Stack trace:
PHP   1. {main}() /usr/local/bin/gush:0
PHP   2. require() /usr/local/bin/gush:10
PHP   3. Gush\Application->__construct() phar:///usr/local/bin/gush/bin/gush:86
PHP   4. Symfony\Component\Console\Application->addCommands() phar:///usr/local/bin/gush/src/Application.php:119
PHP   5. Gush\Application->add() phar:///usr/local/bin/gush/vendor/symfony/console/Symfony/Component/Console/Application.php:384
PHP   6. Symfony\Component\EventDispatcher\EventDispatcher->dispatch() phar:///usr/local/bin/gush/src/Application.php:144
PHP   7. Symfony\Component\EventDispatcher\EventDispatcher->doDispatch() phar:///usr/local/bin/gush/vendor/symfony/event-dispatcher/Symfony/Component/EventDispatcher/EventDispatcher.php:53
PHP   8. call_user_func() phar:///usr/local/bin/gush/vendor/symfony/event-dispatcher/Symfony/Component/EventDispatcher/EventDispatcher.php:164
PHP   9. Gush\Subscriber\TemplateSubscriber->decorateDefinition() phar:///usr/local/bin/gush/vendor/symfony/event-dispatcher/Symfony/Component/EventDispatcher/EventDispatcher.php:164
PHP  10. Gush\Helper\TemplateHelper->getCustomTemplate() phar:///usr/local/bin/gush/src/Subscriber/TemplateSubscriber.php:53

Fatal error: Call to a member function has() on a non-object in phar:///usr/local/bin/gush/src/Helper/TemplateHelper.php on line 66

```

I haven't gone deep into the code but it seems related to the configuration object.

I tried to install it both via composer and via phar and I got the same error.

I'm currently on a mac with php 5.5.3