Open Stack

Hi all,

I'd like to request a feature freeze exception to get the following
change in for castellan.

https://review.openstack.org/#/c/575800/

This extends the functionality of the vault backend to provide
previously uninmplemented functionality, so it should not break anyone.

The castellan vault plugin is used behind barbican in the barbican-
vault plugin.  We'd like to get this change into Rocky so that we can
release Barbican with complete functionality on this backend (along
with a complete set of passing functional tests).

Thanks,
Ade