multi: replace DefaultDustLimit with script-specific DustLimitForSize

This commit updates call-sites to use the proper dust limits for
various script types. This also updates the default dust limit used
in the funding flow to be 354 satoshis instead of 573 satoshis.

lnwallet/reservation.go

@@ -205,6 +205,9 @@ func NewChannelReservation(capacity, localFundingAmt btcutil.Amount,
 		feeMSat += 2 * lnwire.NewMSatFromSatoshis(anchorSize)
 	}
 
+	// Used to cut down on verbosity.
+	defaultDust := wallet.Cfg.DefaultConstraints.DustLimit
+
 	// If we're the responder to a single-funder reservation, then we have
 	// no initial balance in the channel unless the remote party is pushing
 	// some funds to us within the first commitment state.
@@ -218,7 +221,7 @@ func NewChannelReservation(capacity, localFundingAmt btcutil.Amount,
 		if int64(theirBalance) < 0 {
 			return nil, ErrFunderBalanceDust(
 				int64(commitFee), int64(theirBalance.ToSatoshis()),
-				int64(2*DefaultDustLimit()),
+				int64(2*defaultDust),
 			)
 		}
 	} else {
@@ -247,7 +250,7 @@ func NewChannelReservation(capacity, localFundingAmt btcutil.Amount,
 		if int64(ourBalance) < 0 {
 			return nil, ErrFunderBalanceDust(
 				int64(commitFee), int64(ourBalance),
-				int64(2*DefaultDustLimit()),
+				int64(2*defaultDust),
 			)
 		}
 	}
@@ -257,21 +260,21 @@ func NewChannelReservation(capacity, localFundingAmt btcutil.Amount,
 	// reject this channel creation request.
 	//
 	// TODO(roasbeef): reject if 30% goes to fees? dust channel
-	if initiator && ourBalance.ToSatoshis() <= 2*DefaultDustLimit() {
+	if initiator && ourBalance.ToSatoshis() <= 2*defaultDust {
 		return nil, ErrFunderBalanceDust(
 			int64(commitFee),
 			int64(ourBalance.ToSatoshis()),
-			int64(2*DefaultDustLimit()),
+			int64(2*defaultDust),
 		)
 	}
 
 	// Similarly we ensure their balance is reasonable if we are not the
 	// initiator.
-	if !initiator && theirBalance.ToSatoshis() <= 2*DefaultDustLimit() {
+	if !initiator && theirBalance.ToSatoshis() <= 2*defaultDust {
 		return nil, ErrFunderBalanceDust(
 			int64(commitFee),
 			int64(theirBalance.ToSatoshis()),
-			int64(2*DefaultDustLimit()),
+			int64(2*defaultDust),
 		)
 	}