render :partial => '/top_level_partial' should find app/views/_top_level_partial.html.erb

In edge there are MissingTemplate exceptions arising from calls to render :partial for "top-level" partials that have been working up until 2.1.

I am attaching a proposed solution to this ticket as a patch and putting a pull request on github. (Don't know if doing the latter without review of the patch is bad form.) (?)

I'm open to any better way to achieve the behavior in these tests, but I have opted for the very explicit approach.