title: django authentication without a password
body: <p>I'm using the default authentication system with django, but I've added on an OpenID library, where I can authenticate users via OpenID.  What I'd like to do is log them in, but it seems using the default django auth system, I need their password to authenticate the user.  Is there a way to get around this without actually using their password?  </p>
  
  <p>I'd like to do something like this...</p>
  
  <pre><code>user = ... # queried the user based on the OpenID response
  user = authenticate(user) # function actually requires a username and password
  login(user)
  </code></pre>
  
  <p>I sooner just leave off the <code>authenticate</code> function, but it attaches a <code>backend</code> field, which is required by login.  </p>