Fix rspec deprecation warnings about loading order

Running `rspec` gives the following deprecation warnings:

```
*** Mocha deprecation warning: Change `require 'mocha'` to `require 'mocha/setup'`.


*** Mocha deprecation warning: Test::Unit or MiniTest must be loaded *before* Mocha.


*** Mocha deprecation warning: If you're integrating with a test library other than Test::Unit or MiniTest, you should use `require 'mocha/api'` instead of `require 'mocha'`.
```

This corrects them. Still not sure what's up w/ the Puppet error on to_proc, I'm not Puppet-savvy enough to trace it down