Reformat list of config file paths
Merge pull request #1 from alphagov/reformat-config-paths

Reformat list of config file paths
Fix Bunny config.

- It only takes symbol keys as options :/
- Use a unique user and exchange for tests
- More clarity in test setup
- Don't redeclare the exchange when writing
Merge pull request #6 from alphagov/fix-rabbmitmq-config

Fix Bunny config.
Use GOVUK_ENV as our environment flag.

This is already set on all systems; easier than
creating our own.