An fsrep.Replication is either Ready, Retry or in a terminal state.
The queue prefers Ready over Retry:
Ready is sorted by nextStepDate to progress evenly..
Retry is sorted by error count, to de-prioritize filesystems that fail
often. This way we don't get stuck with individual filesystems
and lose other working filesystems to the watchdog.
fsrep.Replication no longer blocks in Retry state, we have
replication.WorkingWait for that.
