Fix cinder command execution issue with a token

This commit fixes the issue where the following error occurs when
executing cinder commands using a token:
> ERROR: argument --os-token: conflicting option string: --os-token

This issue arises because `os_token` is added to the parser in
`keystoneauth1.loading.register_auth_argparse_arguments()`, and then
`os_token` is set again by `parser.add_argument('--os-token')`.

Closes-Bug: #2061349
Change-Id: I8d1ff0f202bec24ed2982108b6cbba1b7981b356

Author: TatsuyaHayashino

cinderclient/shell.py

@@ -331,10 +331,7 @@ def _append_global_identity_args(self, parser):
         parser.add_argument('--os_region_name',
                             help=argparse.SUPPRESS)
 
-        parser.add_argument(
-            '--os-token', metavar='<token>',
-            default=utils.env('OS_TOKEN'),
-            help=_('Defaults to env[OS_TOKEN].'))
+        parser.set_defaults(os_token=utils.env('OS_TOKEN'))
         parser.add_argument(
             '--os_token',
             help=argparse.SUPPRESS)