cliff.commandmanager.CommandManager gained an option, update
openstackclient.common.commandmanager.ComamndManager to match.
Also add CommandManager.get_command_groups() to return a list of the
currently loaded command groups. I expect this to be useful in
upcoming client diagnostic commands for plugins/extensions.
If these turn out to be generally useful we'll propose them to
upstream cliff.
Change-Id: Ic15a7ca0ef975ca679e753be861be7c628b8e10c
* Use multiple entry point groups to represent each API+version
combination supported
* Add some tests
Try it out:
* Right now only '* user' commands have multiple overlapping versions;
you can see the selection between v2.0 and v3 by looking at the
command help output for 'tenant' vs 'project':
os --os-identity-api-version=2.0 help set user
os --os-identity-api-version=3 help set user
Change-Id: I7114fd246843df0243d354a7cce697810bb7de62
