The keypair of a server is updated when rebuilding the server with a
keypair. This function has been added since API microversion 2.54.
However the 'keypairs' of the instance object is not saved when saving
the instance object currently.
Make the instance object update the 'keypairs' field when saving the
Co-authored-by: Stephen Finucane <firstname.lastname@example.org>
(cherry picked from commit