VM Snapshot stuck at Expunging with KvmFileBasedStorageVmSnapshotStrategy

### problem

`KvmFileBasedStorageVmSnapshotStrategy.deleteVMSnapshot` transitions the VM snapshot to `Expunging` during delete but doesn't transition it to `Error` state in case of exception or timeout

`VMSnapshotManagerImpl.hasActiveVMSnapshotTasks` counts `Expunging` as work in
progress, so operations like reboot and snapshot operations are blocked.

### versions

4.22

### The steps to reproduce the bug

1. Take a disk-only VM snapshot.
2. Write lots of data to the VM
3. set commands.timeout=MergeDiskOnlyVmSnapshotCommand=20
4. Delete the snapshot.

...

### What to do about it?

Snapshot state should transition to Error in case of timeout

Comece com KvmFileBasedStorageVmSnapshotStrategy.deleteVMSnapshot e VMSnapshotManagerImpl.hasActiveVMSnapshotTasks e, em seguida, reproduza a exclusão de um snapshot somente de disco com commands.timeout=MergeDiskOnlyVmSnapshotCommand=20. Rastreie o caminho de timeout ou exceção e verifique se o snapshot chega a Error em vez de permanecer em Expunging, para que as reinicializações e as operações de snapshot posteriores não sejam mais bloqueadas.

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