title: Symfony3 + Assetic : ParameterNotFoundException
body: <p>I'm working on a Symfony 3.4 application. Assetic bundle wasn't installed, so I made :</p>
  
  <pre><code>$ composer require symfony/assetic-bundle
  </code></pre>
  
  <p>and add it in the appKernel.php :</p>
  
  <pre><code>    new Symfony\Bundle\AsseticBundle\AsseticBundle(),
  </code></pre>
  
  <p>It worked perfect. Then, in my app/config/config.yml, I added :</p>
  
  <pre><code># app/config/config.yml
  assetic:
      debug:          '%kernel.debug%'
      use_controller: '%kernel.debug%'
      filters:
          cssrewrite: ~
  
  # ...
  </code></pre>
  
  <p>and now my front-end is no more available, this is the error displayed with app_dev.php :</p>
  
  <p><a href="https://i.stack.imgur.com/HYiK6.jpg" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/HYiK6.jpg" alt="enter image description here"></a></p>
  
  <blockquote>
    <p>ParameterNotFoundException You have requested a non-existent parameter
    "templating.engines".</p>
  </blockquote>
  
  <p>Even if I remove the Assetic configuration out of the config.yml the error is here. I have been searching in all my *.yml files I do not find any property "templating.engines" .... any idea ?</p>