Provide the default get_auth_ref implementation

osc-lib tries to call it, failing for e.g. http_basic.

Change-Id: Iacfba0940beda4dce2a9be0c863cb506d4013e2f

keystoneauth1/plugin.py

@@ -61,6 +61,17 @@ class BaseAuthPlugin(object):
         """
         return None
 
+    def get_auth_ref(self, session, **kwargs):
+        """Return the authentication reference of an auth plugin.
+
+        There are no required kwargs. They are passed directly to the auth
+        plugin and they are implementation specific.
+
+        :param session: A session object to be used for communication
+        :type session: keystoneauth1.session.session
+        """
+        return None
+
     def get_headers(self, session, **kwargs):
         """Fetch authentication headers for message.
 

releasenotes/notes/get-auth-ref-7418e13bd0942060.yaml

@@ -0,0 +1,5 @@
+---
+fixes:
+  - |
+    Fixes missing ``get_auth_ref`` call for the ``none`` and ``http_basic``
+    authentication plugins. The implementation simply returns ``None``.