channeldb+lnwallet: store revocation log using the new format

This commit removes the usage of the old revocation log bucket and
starts to perform db operations using the new sub-bucket.

channeldb/db_test.go

@@ -409,7 +409,9 @@ func TestRestoreChannelShells(t *testing.T) {
 	if err != ErrNoRestoredChannelMutation {
 		t.Fatalf("able to mutate restored channel")
 	}
-	err = channel.AdvanceCommitChainTail(nil, nil)
+	err = channel.AdvanceCommitChainTail(
+		nil, nil, dummyLocalOutputIndex, dummyRemoteOutIndex,
+	)
 	if err != ErrNoRestoredChannelMutation {
 		t.Fatalf("able to mutate restored channel")
 	}