title: Symfony2 updating bootstrap.php.cache
body: <p>Recently I started a project in Symfony2 from the BETA version available on symfony.com</p>
  
  <p>After a while, I needed to upgrade to the master branch, so I retrieved the latest from github and switched it in vendor/symfony.</p>
  
  <p>However, my bootstrap.php.cache and bootstrap_cache.php.cache are not upgraded, which has generated errors. </p>
  
  <p>I tried clearing the symfony cache, to no avail.</p>
  
  <p>How can I update these files to correspond to my project?</p>