Every pass attempted every request, each came back "no download clients
are enabled", and RecordAttempt wrote that down as an attempt and put a
retry on the clock -- so a wanted list built deliberately without a
client accrued failures and announced "next check in 6 hours" about a
check that cannot happen.
Wanting something with no way to fetch it is supported. Being told it
is being looked for is a lie, and the row says what is true instead.
Everything above the attempt still runs: an artist subscription still
expands, and a request satisfied by some other route -- ripped, bought,
copied in -- is still retired. Neither needs a provider.
TestReconcileRespectsBatchSize now installs a client that finds
nothing, because a batch size is about how many requests one pass
searches for and that only means something when there is something to
search with.
Refs #37