multi: add labels to lnd native transactions

Follow up labelling of external transactions with labels for the
transaction types we create within lnd. Since these labels will live
a life of string matching, a version number and rigid format is added
so that string matching is less painful. We start out with channel ID,
where available, and a transaction "type". External labels, added in a
previous PR, are not updated to this new versioned label because they
are not lnd-initiated transactions. Label matching can check this case,
then check for a version number.

utxonursery.go

@@ -11,10 +11,10 @@ import (
 	"github.com/btcsuite/btcd/wire"
 	"github.com/btcsuite/btcutil"
 	"github.com/davecgh/go-spew/spew"
-
 	"github.com/lightningnetwork/lnd/chainntnfs"
 	"github.com/lightningnetwork/lnd/channeldb"
 	"github.com/lightningnetwork/lnd/input"
+	"github.com/lightningnetwork/lnd/labels"
 	"github.com/lightningnetwork/lnd/lnwallet"
 	"github.com/lightningnetwork/lnd/sweep"
 )
@@ -867,7 +867,8 @@ func (u *utxoNursery) sweepCribOutput(classHeight uint32, baby *babyOutput) erro
 
 	// We'll now broadcast the HTLC transaction, then wait for it to be
 	// confirmed before transitioning it to kindergarten.
-	err := u.cfg.PublishTransaction(baby.timeoutTx, "")
+	label := labels.MakeLabel(labels.LabelTypeSweepTransaction, nil)
+	err := u.cfg.PublishTransaction(baby.timeoutTx, label)
 	if err != nil && err != lnwallet.ErrDoubleSpend {
 		utxnLog.Errorf("Unable to broadcast baby tx: "+
 			"%v, %v", err, spew.Sdump(baby.timeoutTx))