title: curious failure of auto-conversion to string in python
body: <p>This happened (Python 2.7.13 - Linux):</p>
  
  <pre><code>import SimpleHTTPServer, SocketServer
  
  httpd = SocketServer.TCPServer(("", 8080), SimpleHTTPServer.SimpleHTTPRequestHandler)
  # this fails:
  print "%s" % (httpd.socket.getsockname())
  # this does not:
  print "%s%s" % (httpd.socket.getsockname(), '')
  </code></pre>
  
  <p>Is it considered a bug?</p>