Cookie was only deleted from current path

When deleting a cookie using `->setCookie('cookieName')` code, then only cookie from current path was deleted. This way if cookie was set on `/index.html` page, then it could not be deleted, while being on `/sub-folder/sub-page.html`.

Similar issue for MinkSahiDriver, but with `->reset()` method: https://github.com/Behat/MinkSahiDriver/pull/22