title: Symfony Cache Component (3.1) not saving cache
body: <p>I'm using the new Symfony Cache Component. I generate my cache first with a command (Command/AppCacheGenerateCommand.php):</p>
  
  <pre><code>$cache = new FilesystemAdapter();         
  foreach ($domains as $domain){
          if ($domain-&gt;getHost()){
              $output-&gt;writeln('Generate cache for domain: ' . $domain-&gt;getHost());
              $domainCache = $cache-&gt;getItem('domain.' . $domain-&gt;getHost());
              $domainCache-&gt;set($domain-&gt;getId());
              $cache-&gt;save($domainCache);
          }
      }
  </code></pre>
  
  <p>Then trying to get these cached elements in a onKernelRequest EventListener (EventListener/RequestListener.php)</p>
  
  <pre><code>$cache = new FileSystemAdapter();
      $domainCache = $cache-&gt;getItem('domain.' . $host);
      if (!$domainCache-&gt;isHit()){
          die;
      }
  </code></pre>
  
  <p>It's always dies here, not going further. Anyone can give me an explanation? (I've tried if the host not matching, but it does...)</p>