commands: refactor the default auth version stuff
commands: refactor the default auth version stuff

Instead of specifying the default in the command line arg definition,
this is handled else where (see _get_zerocloud_conn and
_guess_auth_version).

zerovm/zerovm-cli,zerovm/zpm,zerovm/zerovm-cli,zerovm/zerovm-cli,zerovm/zpm,zerovm/zerovm-cli,zerovm/zerovm-cli,zerovm/zpm,zerovm/zerovm-cli,zerovm/zpm,zerovm/zpm,zerovm/zpm