title: convert_tz returns null
body: <p>I know this sounds stupid, but when I use</p>
  
  <pre><code>SELECT CONVERT_TZ('2004-01-01 12:00:00','UTC','Asia/Jakarta') AS time
  </code></pre>
  
  <p>it outputs NULL. I'm using MySQL Workbench in Ubuntu 12.04 64 bit, and it works in my other laptop/os (also using MySQL Workbench).</p>