Comment 2 for bug 1894381

Reviewed: https://review.opendev.org/750077
Committed: https://git.openstack.org/cgit/openstack/cinder/commit/?id=50a4592efb39902b994470a229dff7b37810727b
Submitter: Zuul
Branch: master

commit 50a4592efb39902b994470a229dff7b37810727b
Author: czl389 <czl389@163.com>
Date: Sun Sep 6 00:48:32 2020 +0800

    Fix cinder-manage cluster remove raising NoSuchOptError

    When executing 'cinder-manage cluster remove' script, an error occurs in
    the call 'fetch_func_args(fn)':
    oslo_config.cfg.NoSuchOptError:no such option cluster_name in group
    [DEFAULT].

    The cause is that the call 'fetch_func_args(fn)' is trying to fetch
    value of argument 'cluster_name' of fn from CONF.cluster_name, but
    corresponding argument registered in CONF is 'cluster-name' actually.

    We fix this bug by changing argument name registered in CONF, if
    positional argument contains '-':
    1.put it into automatic conversion from '- to '_', so that keep it the
     same name as handler function argument.
    2.add metavar if it doesn't already exist, and it will maintain the help
     output.

    Change-Id: I3f2a04b4c8e7bafe6e38fc86a69192dd3a94c0c5
    Closes-Bug: #1894381