The Generic Driver in Manila has no concept of consistency
groups. This patch proposes to implement a loose
consistency group support mechanism for the Generic Driver,
using existing logic to snapshot shares and create shares
from snapshots.
The actions concerning creating and deleting a consistency
group are handled by the API and the Generic Driver does not
need to remember any relevant information persistently.
The actions concerning consistency group snapshots are not
simultaneous, but are rather let to run in succession.
DocImpact
Partially implements bp manila-consistency-groups
Change-Id: Ie5e51205a1154786f9057691aa82bffcafe04de7