Rename handle_snapshot and pass state

Rename handle_snapshot() to handle_snapshot_delete() to better reflect what
it needs to do (both take a snapshot of the resource and then delete the
resource). Also, pass the state of the resource prior to delete being
invoked, since the resource may want to use different error handling in the
snapshot phase depending on e.g. whether the resource was created
successfully or not.

Change-Id: I1e5aaab4f13e42333c1f2f39bfeb0ebf2ac89ed8
Merge "Rename handle_snapshot and pass state"