Fixed Deprecation Warning in Rails 2.3.10

Hey, I am updating an app to Rails 2.3.10 and noticed that there was a deprecation warning about Kernel#returning being replaced with Object#tap. It was filling my screen when running tests so I decided to fix it.

I noticed there weren't any tests for the Rails2 stuff so I didn't have any concrete way to know if what I did works 100%. I would be happy to add tests to make sure it still work ok, just let me know how you would prefer to split the tests based on Rails2 and Rails3.