This patch adds new methods to our failover mechanism to allow failover
to work when a backend is clustered.
Adds REST API microversion 3.26 that adds a new `failover` method
equivalent to `failover_host` but accepting `cluster` field as well as
the `host` field.
Thaw and Freeze are updated to update cluster and all services within
the cluster.
Now cluster listings accepts new filtering fields `replication_status`,
`frozen`, and `active_backend_id`.
Summary listings return `replication_status` field and detailed listings
also return `frozen` and `active_backend_id`.
Specs: https://review.openstack.org/401392
APIImpact: New service failover action and new fields in cluster listings.
Implements: blueprint cinder-volume-active-active-support
Change-Id: Id3291b28242d5814c259283fa629b48f22e70260
b4a13281ea