integration tests do not need to load fixtures by hand

I don't know when this changed, checked back up to 3.2 and integration
tests instantiate fixtures just fine.
Update all Rails 4.1.0 references in guides to 4.1.1 [ci skip]

Conflicts:
	guides/CHANGELOG.md
	guides/code/getting_started/Gemfile
	guides/source/debugging_rails_applications.md