rails/rails — pull request #3581 by amatsuda (2011-11-09 07:15:47+00:00)
Title: AC::Metal#response_body= stores different value in Ruby 1.8 and 1.9

```
AC::Metal#response_body = 'foo'
```
stores `['foo']` in Ruby 1.9 but stores `'foo'` in 1.8, because `String#respond_to?(:each)` differs in 1.8 and 1.9.

Although this is just an internal API, app developers sometimes need to directly refer to this value in some cases like monkey patching and testing. So it's nicer if this value doesn't be affected by Ruby version.