core (disco): client.disco.requestInfo failure are re-raised: so far, requestInfo failure where logged as a warning, and an empty disco was returned. This prevented the requesting entity to know about the error, so now the error is logged and re-raised. CancelError are converted to TimeoutError (requestInfo is only cancelled on timeout). An empty disco is still cached in case of failure, to avoid re-waiting for the entity on next request.

[D-BUS Service]
Name=org.salutatoi.SAT
Exec=sat