ruckus/quickbooks-ruby — pull request #175 by jasondew (2014-10-24 13:09:52+00:00)
Title: Throw ServiceUnavailable for HTTP 504s as well as HTTP 503s

Hi there again @ruckus ! We came across this response from QBO and it looks like `Quickbooks::ServiceUnavailable` should fit the bill.

```
HTTP Error Code: 504, Msg:

message=Timeout occurred while proxying request; errorCode=006002; statusCode=504

```

This PR also adds some test coverage for HTTP 503s. Thanks!