Fix publication node form for basic members.

#6405 

This PR fixes the publication form for basic members (and in fact for anyone who don't have access to the "authored by" section on the publication form).

"Michelle" is a basic member in "John":
![selection_423](https://cloud.githubusercontent.com/assets/4497748/3718826/20448e8a-163b-11e4-9dca-bba7519333c1.png)