sweep: Remove publishing last-tx logic.

We remove the publishing of the last published sweep tx during the
startup of the sweeper. This republishing can lead to situations
where funds of the default wallet might be locked for neutrino
backend clients.
Moreover all related tests are removed as well.

sweep/sweeper.go

@@ -340,30 +340,6 @@ func (s *UtxoSweeper) Start() error {
 
 	log.Info("Sweeper starting")
 
-	// Retrieve last published tx from database.
-	lastTx, err := s.cfg.Store.GetLastPublishedTx()
-	if err != nil {
-		return fmt.Errorf("get last published tx: %v", err)
-	}
-
-	// Republish in case the previous call crashed lnd. We don't care about
-	// the return value, because inputs will be re-offered and retried
-	// anyway. The only reason we republish here is to prevent the corner
-	// case where lnd goes into a restart loop because of a crashing publish
-	// tx where we keep deriving new output script. By publishing and
-	// possibly crashing already now, we haven't derived a new output script
-	// yet.
-	if lastTx != nil {
-		log.Debugf("Publishing last tx %v", lastTx.TxHash())
-
-		// Error can be ignored. Because we are starting up, there are
-		// no pending inputs to update based on the publish result.
-		err := s.cfg.Wallet.PublishTransaction(lastTx, "")
-		if err != nil && err != lnwallet.ErrDoubleSpend {
-			log.Errorf("last tx publish: %v", err)
-		}
-	}
-
 	// Retrieve relay fee for dust limit calculation. Assume that this will
 	// not change from here on.
 	s.relayFeeRate = s.cfg.FeeEstimator.RelayFeePerKW()