osd: make sure _finish_recovery only completes when it's supposed to

osd: make sure _finish_recovery only completes when it's supposed to

Because the finish_recovery does a sync, the final cleanup is
deferred, and we have to make sure we are still done (and we
haven't, say, repeered or something).

In this case, we thus make sure we don't clear out pg
recovery_ops when we actually have ops in progress.