Accept the configuration_version as alternative in the report view.

[puppet-hipchat](https://github.com/jamtur01/puppet-hipchat) has this very helpful feature where the puppet runs that are logged in the chat are posted with a link to the report.

Unfortunately, for now only the '/latest' report can be linked as the report hash is not available in the puppet report format.

I thought the easiest way to change this is to optionally accept the configuration_version as the `<report_id>`. It's a tiny change really, but it would help solve this problem:

https://github.com/jamtur01/puppet-hipchat/pull/23#discussion-diff-10535251

We'll then end up with this:
![screenshot of google chrome 10-09-14 16 41 34](https://cloud.githubusercontent.com/assets/273163/4219287/a486c9d0-38f8-11e4-9614-21f251f4def5.png)