pool: daemon crashes if unable to reconcile local order state w/ a replaced pending batch

[Roasbeef]

Reported by a Lightning Terminal user:

[ERR] LITD: Could not start subservers: unable to start account manager: unable to resume account X: unable to subscribe for account updates: checking pending batch failed: error removing pending batch artifacts: error abandoning channels from previous pending batch: error locating channel outpoint: no channel output found in batch tx for matched order Y

The start of the failed code path is here: https://github.com/lightninglabs/pool/blob/master/auctioneer/client.go#L579-L587

We go to abandon the channel shims we have have created:

pool/funding/manager.go

Lines 999 to 1005 in 3e49f4c

	// Also abandon any channels that might still be pending
	// from a previous round of the same batch or a previous
	// batch that we didn't make it into the final round.
	err = AbandonCanceledChannels(
	matchedOrders, batchTx, m.cfg.WalletKit, m.cfg.BaseClient,
	m.cfg.DB.GetOrder,
	)

Ultimately failing here when it can't find an output its looking for in the batch execution transaction:

pool/funding/batch.go

Lines 95 to 105 in 3e49f4c

	// For each ask order that was matched with this bid, we'll
	// locate the channel outpoint then abandon it from lnd's
	// channel database.
	for _, matchedOrder := range matchedOrders {
	_, idx, err := order.ChannelOutput(
	batchTx, wallet, ourOrder, matchedOrder,
	)
	if err != nil {
	return fmt.Errorf("error locating channel "+
	"outpoint: %v", err)
	}