Ignore domain related config when using with keystone v2

Currently, "/usr/bin/openstack --insecure token issue"
fails when OS_AUTH_URL and OS_IDENTITY_API_VERSION
indicate keystone v2 if OS_PROJECT_DOMAIN_NAME or
OS_USER_DOMAIN_NAME are set. This patchset ignore domain
related configs if using with keystone v2 and print warning
for each ignored config.

Change-Id: I8afbda787df7855c3f8e868b0f07cbf3b9cd97fd
Closes-bug: #1447704

Author: Hieu LE

openstackclient/common/clientmanager.py

@@ -200,12 +200,12 @@ def setup_auth(self, required_scope=True):
         # ignore all domain related configs.
         if (self._api_version.get('identity') == '2.0' and
                 self.auth_plugin_name.endswith('password')):
-            LOG.warning("Ignoring domain related configs "
-                        "because identity API version is 2.0")
             domain_props = ['project_domain_name', 'project_domain_id',
                             'user_domain_name', 'user_domain_id']
             for prop in domain_props:
-                self._auth_params.pop(prop, None)
+                if self._auth_params.pop(prop, None) is not None:
+                    LOG.warning("Ignoring domain related configs " +
+                                prop + " because identity API version is 2.0")
 
         # For compatibility until all clients can be updated
         if 'project_name' in self._auth_params: