syncoid: polish conf while debugging

syncoid: polish conf while debugging

Current config of syncoid transfers only the oldest new snapshot
at each run. This causes the following error message:
> cannot receive incremental stream: most recent snapshot of
> losurdo/backup/mermet/home/julm/log
> does not match incremental source
after the transfer of that snapshot until there is no newer snapshots.
But when a snapshot is taken each hour and a transfer only happens each hour,
syncoid never catches up, and thus keeps issuing the error message.