Selective backports
    
    Resolves: rhbz#1101014
    
    Changelog:
    - Selective backports (server groups and more)
    - Nova CLI for server groups (rhbz#1101014)
    - Enable delete multiple server groups in one request
    - Fix session handling in novaclient
    - Fix authentication bug when booting an server in V3
    - Avoid AttributeError in servers.Server.__repr__