I'm thinking we should remove this rescue, for a couple reasons:

* The suggestion it has (adding `rubygems` as a `RUBYOPT`) only helps on 1.8. On 1.9+, rubygems is built-in.
* This `rescue LoadError` has hidden issues from me before -- for example, when doing an rspec-core refactoring, I renamed a file but forgot to update the `require` statement that loaded it.  The rescue of the `LoadError` here silenced the useful error that would have quickly told me that the old file name was still being required.