title: can't access github via https after upgrade to Yosemite
body: <p>I can't access GitHub via https after upgrade my Mac to Yosemite.</p>
  
  <pre><code>fatal: unable to access 'https://github.com/caskroom/homebrew-cask/': SSL: can't load CA certificate file
  </code></pre>
  
  <p>Actually,it's brew update,most of brew operations are via https when requesting github repo.</p>