Resource format not guessed automatically

[WIP] The resource format isn't guessed automatically, but CKAN claims to guess it automatically. I recommend removing the text for for 2.2 and fix guessing for 2.3.

![automatically](https://f.cloud.github.com/assets/373438/1648665/fb88b40a-59b0-11e3-9822-e9979d7569ca.png)