sweepbatcher: always try greedy batch selection

Now that sweep.minFeeRate is always set, greedy batch selection has all needed
inputs to work even without customFeeRate provider.

sweepbatcher/greedy_batch_selection.go

@@ -28,11 +28,6 @@ import (
 // creation fails, this method returns an error. If this method fails for any
 // reason, the caller falls back to the simple algorithm (method handleSweep).
 func (b *Batcher) greedyAddSweep(ctx context.Context, sweep *sweep) error {
-	if b.customFeeRate == nil {
-		return errors.New("greedy batch selection algorithm requires " +
-			"setting custom fee rate provider")
-	}
-
 	// Collect weight and fee rate info about the sweep and new batch.
 	sweepFeeDetails, newBatchFeeDetails, err := estimateSweepFeeIncrement(
 		sweep,

sweepbatcher/sweep_batcher.go

@@ -474,19 +474,16 @@ func (b *Batcher) handleSweep(ctx context.Context, sweep *sweep,
 		}
 	}
 
-	// If custom fee rate provider is used, run the greedy algorithm of
-	// batch selection to minimize costs.
-	if b.customFeeRate != nil {
-		err := b.greedyAddSweep(ctx, sweep)
-		if err == nil {
-			// The greedy algorithm succeeded.
-			return nil
-		}
-
-		log.Warnf("Greedy batch selection algorithm failed for sweep "+
-			"%x, falling back to old approach.", sweep.swapHash[:6])
+	// Try to run the greedy algorithm of batch selection to minimize costs.
+	err = b.greedyAddSweep(ctx, sweep)
+	if err == nil {
+		// The greedy algorithm succeeded.
+		return nil
 	}
 
+	log.Warnf("Greedy batch selection algorithm failed for sweep %x: %v. "+
+		"Falling back to old approach.", sweep.swapHash[:6], err)
+
 	// If one of the batches accepts the sweep, we provide it to that batch.
 	for _, batch := range b.batches {
 		accepted, err := batch.addSweep(ctx, sweep)