title: Python os.getlogin problem
body: <p>If i create a file like:</p>
  
  <pre><code>import os
  print os.getlogin()
  </code></pre>
  
  <p>and run it with cron, I get an exception</p>
  
  <pre><code>print os.getlogin()
  OSError: [Errno 22] Invalid argument
  </code></pre>
  
  <p>If I run it manually in shell -- it works.</p>
  
  <p>Problem is, GitPython 0.3.1 in commit() uses this function, and i need to use it.</p>
  
  <p>Is there any workaround?</p>
  
  <p>I've tested it on Ubuntu10.10/python2.6.6 and Debian5.0.6/python2.5.2.</p>