As of Liberty, python-glanceclient started using v2 as the default API version. This means that users running commands without specifying the version explicitly may face some issues as there are some incompatibilities between these 2 versions. For users willing to stick to v1 of the API, it's important to let them know that: `--os-image-api-version 1` must be passed through the CLI. You can find more information about these incompatibilities here: https://wiki.openstack.org/wiki/Glance-v2-v1-client-compatability
Assigning to Charelle for review.
Looks good to me. Merged.