title: Swift time zones converting issue
body: <p>In my playground i create a simple code example to convert time from my local zone to <code>"America/Sao_Paulo"</code>. </p>
  
  <pre><code>let gmtDf: NSDateFormatter = NSDateFormatter()
  gmtDf.timeZone = NSTimeZone.systemTimeZone();
  gmtDf.dateFormat = "HH:mm:ss"
  let gmtDate: NSDate = NSDate.new()
  
  print(gmtDate)
  
  let estDf: NSDateFormatter = NSDateFormatter()
  estDf.timeZone = NSTimeZone(name: "America/Sao_Paulo")
  estDf.dateFormat = "HH:mm:ss"
  let estDate: NSDate = estDf.dateFromString(gmtDf.stringFromDate(gmtDate))!
  
  print(estDate)
  </code></pre>
  
  <p>All code is working fine, but i have a question that is connected with code output.Why printed output show time 2 hours before my local time. And converted time is in 2000 year.</p>
  
  <p><a href="https://i.stack.imgur.com/Qg9yy.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/Qg9yy.png" alt="enter image description here"></a></p>