Clean up crowbar.yml a bit.
Do not rely on a pre-generated set of default attributes.

Figure it out from the repo definitions in the saved crowbar.yml files instead.
Fix up to work properly with build system changes.

Since the main build system now handles caching our git repos, we
don't have to anymore.
Merge pull request #15 from VictorLowther/pull-req-feature-grizzly-master-9a77ef6723b715acfb8d892036d330758f85a940

Make feature/grizzly a little more amenable to being built in the Dell build and test env. [6/11]