Replace storage-url with service-catalog

Replacing storage url with a base 64 encoded service catalog obtained from identity.
This change is required in order to run the tests when the swift driver is used in deuce
Ok - in PR #135 I discovered that I didn't have a test that did the full encoding - service catalog -> json -> b64 encoding. Fixing the test reveals the same problem. After I fix that we can determine if the above needs modified at all.