novaclient.shell fails with OS_AUTH_TYPE=v3kerberos

When OS_AUTH_TYPE is set to v3kerberos or --os-auth-type=v3kerberos is passed, nova shell fails with an error

ERROR (AttributeError): 'Namespace' object has no attribute 'os_user_id'

This is because keystoneauth1 module does not add options unnecessary with kerberos to argparse

The patch below allowed me to use v3kerberos with python-novaclient 10.1.0

--- python-novaclient-10.1.0.org/novaclient/shell.py 2018-01-25 23:37:12.000000000 +0000
+++ python-novaclient-10.1.0.patched/novaclient/shell.py 2018-02-08 18:36:04.671381497 +0000
@@ -513,24 +513,27 @@
             api_version = api_versions.get_api_version(
                 args.os_compute_api_version)

- os_username = args.os_username
- os_user_id = args.os_user_id
+ os_username = getattr(args, 'os_username', None)
+ os_user_id = getattr(args, 'os_user_id', None)
         os_password = None # Fetched and set later as needed
         os_project_name = getattr(
             args, 'os_project_name', getattr(args, 'os_tenant_name', None))
         os_project_id = getattr(
             args, 'os_project_id', getattr(args, 'os_tenant_id', None))
         os_auth_url = args.os_auth_url
+ os_auth_type = getattr(args, 'os_auth_type', 'password')
         os_region_name = args.os_region_name

         if "v2.0" not in os_auth_url:
             # NOTE(andreykurilin): assume that keystone V3 is used and try to
             # be more user-friendly, i.e provide default values for domains
- if (not args.os_project_domain_id and
- not args.os_project_domain_name):
- setattr(args, "os_project_domain_id", "default")
- if not args.os_user_domain_id and not args.os_user_domain_name:
- setattr(args, "os_user_domain_id", "default")
+ if hasattr(args, 'os_project_domain_id'):
+ if (not args.os_project_domain_id and
+ not args.os_project_domain_name):
+ setattr(args, "os_project_domain_id", "default")
+ if hasattr(args, 'os_user_domain_id'):
+ if not args.os_user_domain_id and not args.os_user_domain_name:
+ setattr(args, "os_user_domain_id", "default")

         os_project_domain_id = args.os_project_domain_id
         os_project_domain_name = args.os_project_domain_name
@@ -579,7 +582,7 @@
         # for os_username or os_password but for compatibility it is not.
         if must_auth and not skip_auth:

- if not os_username and not os_user_id:
+ if os_auth_type != 'v3kerberos' and not os_username and not os_user_id:
                 raise exc.CommandError(
                     _("You must provide a username "
                       "or user ID via --os-username, --os-user-id, "