title: SSL verification problems trying to clone git repo with cocoapods
body: <p>I've just created a new Xcode 8 project and I'm trying to install Alamofire via CocoaPods.
  Just after <code>pod install</code> I'm getting this error:</p>
  
  <pre><code>[!] Error installing Alamofire
  [!] /usr/bin/git clone https://github.com/Alamofire/Alamofire.git /var/folders/18/n59jh6715l38t9wsmbgv5yvc0000gp/T/d20160926-3719-16da22u --template= --single-branch --depth 1 --branch 4.0.1
  
  Cloning into '/var/folders/18/n59jh6715l38t9wsmbgv5yvc0000gp/T/d20160926-3719-16da22u'...
  fatal: unable to access 'https://github.com/Alamofire/Alamofire.git/': SSL: certificate verification failed (result: 5)`
  </code></pre>
  
  <p>Last Friday I've installed another library into another Xcode 8 project with no problems at all, so I really don't know what to do.
  In both cases I've used a Macbook Pro with MacOs Sierra.</p>