When the NetApp backend starts, it needs to know whether the
`revert_to_snapshot` support exist. So, it was retrieving the
licenses and checking if the `SnapRestore` is included. Using a
scoped account, the backend cannot retrieve that information,
though. So, this patch solves it by sending a fake operation
`revert_to_snapshot` that must fail. Analyzing the given error, it
sets the backend support field.
Closes-Bug: #1882590
Change-Id: Ib71a6cec939288498e48736f129fbfdacaabe9da
