title: NSMutableURLRequest setValue:forHTTPHeaderField xcode 6.2 not working for "application/json; charset=utf-8"
body: <p>I am developing and app, with Alamofire, in Xcode 6.2, and by default Alamofire has this for .JSON encoding:</p>
  
  <pre><code>mutableURLRequest.setValue("application/json", forHTTPHeaderField: "Content-Type")
  </code></pre>
  
  <p>However, I need value to be like this:</p>
  
  <pre><code>mutableURLRequest.setValue("application/json; charset=utf-8", forHTTPHeaderField: "Content-Type")
  </code></pre>
  
  <p>The problem is that after this line, if I print allHTTPHeaderFields, I have:</p>
  
  <pre><code>(lldb) po mutableURLRequest.allHTTPHeaderFields!.description
  "[Content-Type: application/json]"
  </code></pre>
  
  <p>Note: This is only happening in Xcode 6.2. It's working perfect in Xcode 6.1.1</p>
  
  <p>Anybody can help? Thanks in advance.</p>