Fixing Broken HTTP Auth

If you attempt to login to a site with http auth, you get this message:
![image](https://cloud.githubusercontent.com/assets/437043/3706414/45ae79ec-1429-11e4-800b-1915201282ac.png)

This issue was fixed over here(https://github.com/wordpress-mobile/WordPressApi/pull/20) and this pull request just pulls in the changes.