channeldb: remove RevocationDelay field from the HTLC struct

This commit removes the RevocationDelay field from the HTLC struct as
with the latest commitment transaction scheme, it is no longer needed.
This is due to the fact the the delay is now observed when an on-chain
HTLC claim is attempted, rather than from Shane the HTLC itself has
been broadcast.

channeldb/channel_test.go

@@ -205,12 +205,11 @@ func TestOpenChannelPutGetDelete(t *testing.T) {
 	}
 	state.Htlcs = []*HTLC{
 		{
-			Signature:       testSig.Serialize(),
-			Incoming:        true,
-			Amt:             10,
-			RHash:           key,
-			RefundTimeout:   1,
-			RevocationDelay: 2,
+			Signature:     testSig.Serialize(),
+			Incoming:      true,
+			Amt:           10,
+			RHash:         key,
+			RefundTimeout: 1,
 		},
 	}
 	if err := state.FullSync(); err != nil {
@@ -348,18 +347,19 @@ func TestChannelStateTransition(t *testing.T) {
 			incoming = true
 		}
 		htlc := &HTLC{
-			Signature:       testSig.Serialize(),
-			Incoming:        incoming,
-			Amt:             10,
-			RHash:           key,
-			RefundTimeout:   i,
-			RevocationDelay: i + 2,
-			OutputIndex:     int32(i * 3),
+			Signature:     testSig.Serialize(),
+			Incoming:      incoming,
+			Amt:           10,
+			RHash:         key,
+			RefundTimeout: i,
+			OutputIndex:   int32(i * 3),
 		}
 		htlcs = append(htlcs, htlc)
 		htlcAmt += htlc.Amt
 	}
 
+	// TODO(roasbeef): ensure that expiry matches
+
 	// Create a new channel delta which includes the above HTLCs, some
 	// balance updates, and an increment of the current commitment height.
 	// Additionally, modify the signature and commitment transaction.