multi: update funding workflow to be aware of new tweakless commits

In this commit, we update the funding workflow to be aware of the new
channel type that doesn't tweak the remote party's output within the
non-delay script on their commitment transaction. To do this, we now
allow the caller of `InnitChannelReservation` to signal if they want the
old or new (tweakless) commitment style.

The funding tests are also updated to test both funding variants, as
we'll still need to understand the legacy format for older nodes.

lnwallet/reservation.go

@@ -130,7 +130,8 @@ type ChannelReservation struct {
 func NewChannelReservation(capacity, localFundingAmt btcutil.Amount,
 	commitFeePerKw SatPerKWeight, wallet *LightningWallet,
 	id uint64, pushMSat lnwire.MilliSatoshi, chainHash *chainhash.Hash,
-	flags lnwire.FundingFlag) (*ChannelReservation, error) {
+	flags lnwire.FundingFlag,
+	tweaklessCommit bool) (*ChannelReservation, error) {
 
 	var (
 		ourBalance   lnwire.MilliSatoshi
@@ -140,7 +141,7 @@ func NewChannelReservation(capacity, localFundingAmt btcutil.Amount,
 
 	commitFee := commitFeePerKw.FeeForWeight(input.CommitWeight)
 	localFundingMSat := lnwire.NewMSatFromSatoshis(localFundingAmt)
-	// TODO(halseth): make method take remote funding amount direcly
+	// TODO(halseth): make method take remote funding amount directly
 	// instead of inferring it from capacity and local amt.
 	capacityMSat := lnwire.NewMSatFromSatoshis(capacity)
 	feeMSat := lnwire.NewMSatFromSatoshis(commitFee)
@@ -213,7 +214,11 @@ func NewChannelReservation(capacity, localFundingAmt btcutil.Amount,
 	// non-zero push amt (there's no pushing for dual funder), then this is
 	// a single-funder channel.
 	if ourBalance == 0 || theirBalance == 0 || pushMSat != 0 {
-		chanType = channeldb.SingleFunder
+		if tweaklessCommit {
+			chanType = channeldb.SingleFunderTweakless
+		} else {
+			chanType = channeldb.SingleFunder
+		}
 	} else {
 		// Otherwise, this is a dual funder channel, and no side is
 		// technically the "initiator"