Enhance the code that migrates the ConfKeyManager's fixed_key to
Barbican to also consider the Backup table. When the original key
migration feature was added, the encryption key ID was not stored in
the Backup table. But now the Backup table contains that field, so
the migration code needs to handle that table as well.
Whereas the cinder-volume service is responsible for migrating keys
in the Volume and Snapshot tables, the cinder-backup service handles
migrating keys in the Backup table. Each instance of the service
migrates its own entries by matching the "host" field in the
corresponding tables.
The Backup OVO now inherits from base.CinderComparableObject. This does
not affect the object's hash signature, and so the version number does
need to be incremented.
Closes-Bug: #1757235
Change-Id: Id4581eec80f82925c20c424847bff1baceda2349
341dd44ba7