Provide a null log function for OpenID to keep it from spewing during tests

Removes the three blot messages from this output:

```
.........----..........................................Generated checkid_setup request to http://testserver/openid/provider/login/ with assocication {HMAC-SHA1}{51db1888}{hGUNRw==}
.Generated checkid_setup request to http://testserver/openid/provider/login/ with assocication {HMAC-SHA1}{51db1888}{7hK/iw==}
.....................
.............................................................................
.............................................................................
.............................................................................
.............................................................................
.......................Generated checkid_setup request to http://testserver/openid/provider/login/ with assocication {HMAC-SHA1}{51db1914}{U3rCMQ==}
..--......
```

Nicer, right, @jzoldak and @cpennington ?