title: composer update on mac not working
body: <p>Since I updated my PHP version to 5.4, I have trouble to update composer on my symphony 2 project.</p>
  
  <pre><code>$ php composer.phar update
  </code></pre>
  
  <p>gives me:</p>
  
  <pre><code>The "https://packagist.org/packages.json" file could not be downloaded: php_network_getaddresses: getaddrinfo failed: nodename nor servname provided, or not known
  failed to open stream: php_network_getaddresses: getaddrinfo failed: nodename nor servname provided, or not known
  _https://packagist.org could not be fully loaded, package information was loaded from the local cache and may be out of date
  
  
    [RuntimeException]
    Failed to execute git status --porcelain --untracked-files=no
  
    error: bad index file sha1 signature
    fatal: index file corrupt
  </code></pre>
  
  <p>Here is link to a screenshot:</p>
  
  <p><a href="http://sanofuzir.com/Screen.jpg" rel="nofollow">http://sanofuzir.com/Screen.jpg</a></p>
  
  <p>What should I do?</p>