Reverse result, exit_code in capture2e output.

In the file `puppet_catalog_diff_spec.rb`, on line 43 shouldn't `exit_code` and `result` be reversed, according to the [documentation ](https://docs.ruby-lang.org/en/2.0.0/Open3.html) for capture2e where result comes first and exit_code second, such as the given example `stdout_and_stderr_str, status = Open3.capture2e([env,] cmd... [, opts])`?
