--no-ask still leads to bad credentials.

```
@unrebased-prs ~/code/scc.git $ (cd ~/git; ~/code/scc.git/scc.py unrebased-prs dev_4_4 develop -v --no-ask)
2013-02-08 10:17:19,307 [  scc.config] DEBUG Found github.user
Bad credentials
```

Likely until something **requires** credentials (push), we should fall back to an unauthenticated connection.
