Add example role for setups w/ external keystone
Rename environments to match documentation

- Rename swift environment to swift-private-cloud
- Rename defailt json to .json.example
Lock Berksfile to known working external deps

Mostly because of the yum 3.x upgrade that we don't yet support across
all cookbooks, locking down the Berksfile deps to known working versions
from stable branch.

This should fix the build server errors for yum 3.x being installed.
Merge pull request #244 from claco/update-berkshelf

Merged automatically by jenkins after successful build test
Merge pull request #242 from claco/external-keystone-role

Merged automatically by jenkins after successful build test
Merge pull request #243 from claco/rename-environments

Merged automatically by jenkins after successful build test