Unimplemented abstract method in SaharaKeyManager causes trouble

[Jeremy Freudberg]

Castellan added a new abstract method in the base class which SaharaKeyManager inherits from. Which will throw a TypeError when trying to instantiate the class.

https://review.openstack.org/#/c/418019/

`TypeError: Can't instantiate abstract class SaharaKeyManager with abstract methods list` was uncovered during building RPM package.

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/491793
Committed: https://git.openstack.org/cgit/openstack/sahara/commit/?id=e96a30d06bf2fa218dee31b80db310bc3cf8f26b
Submitter: Jenkins
Branch: master

commit e96a30d06bf2fa218dee31b80db310bc3cf8f26b
Author: Jeremy Freudberg <email address hidden>
Date: Tue Aug 8 13:11:16 2017 +0000

    Fix unimplemented abstractmethod

    In [0], castellan added a new abstractmethod to the base class which
    SaharaKeyManager inherits from. We need to override this abstractmethod
    with our own dummy function or else face TypeError.

    [0] https://review.openstack.org/#/c/418019/

    Change-Id: Ibac3e8c9086f000029bcb6001643edf24a3951ad
    Closes-Bug: #1709313

[OpenStack Infra (hudson-openstack)]

This issue was fixed in the openstack/sahara 7.0.0.0rc1 release candidate.