title: gitsharp clone http protocol failed, but git protocol success! why?
body: <p>i use gitsharp,
  when i want to clone project by http protocol, 
  i will disappear <a href="http://pic002.cnblogs.com/images/2011/156604/2011090216183593.png" rel="nofollow">"cannot Read available refs"</a></p>
  
  <p>but when i use git protocol to clone the same project frome git hub, it success!</p>