Gazler/rapidash — pull request #21 by paulspringett (2013-07-04 08:56:09+00:00)
Title: Fix issue with ResponseError not exposing it's `message` method publicly

This was causing a further exception when raising the `ResponseError` exception saying

```
rspec-core-2.13.1/lib/rspec/core/formatters/base_text_formatter.rb:264:in `dump_failure_info':
private method `message' called for # (NoMethodError)

```

Changed to use the standard `to_s` which is automatically called when raising.