chrisk/fakeweb — pull request #32 by myronmarston (2012-06-12 15:27:10+00:00)
Title: Return nil when the body is stubbed as '' or nil.

When a real Net::HTTP request is made and receives an
empty-body response (such as a 204 No Content), then the
response body is nil.

This gist demonstrates the behavior:
https://gist.github.com/2918173