Fix two bug about listing snapshotpolicycache:
1. no accont info 2. filter error
The func 'Key' of snapshotpolicy generate a Identification for
snapshotpolicy. If the key of cloud snapshotpolicy is same with local
snaphotpolicy, the cloud sp became a cache of this local sp.
Now, you can take the initiative to push snapshotpolicy to cloud and
view the caches of a snasphotpolicy or delete them.
Add status for snapshotpolicy cache: ready, deleting and delete_failed.