[FLOC-965] Acceptance testing against rackspace.

This is based on #1010. The relative diff is [here](https://github.com/ClusterHQ/flocker/compare/acceptance-runner-FLOC-1070...rackspace-acceptance-FLOC-965).

The linking tests fail due to [FLOC-1084](https://clusterhq.atlassian.net/browse/FLOC-1084).


This was a deliberate choice. There are several pygments processors for shell-like things that unfortunately have disjoint features.

- bash has handling for things like strings and substitutions `${}` and `$()`.
- console has support for prompts, but doesn't highlight the command itself.

I deliberately didn't include prompts here, because I expect people will be copy-pasting at least some of the steps (the kernel one in particular). It doesn't appear that there is any easy way to get prompts that don't get copied (This was my first thought).

Since we don't have prompts, I didn't see any value in using the `console` formating, hence I used `bash`.