test: modify the networkHarness' OpenChannel method to use global IDs

This commit modifies the OpenChannel helper method within the
networkHarness to open the channel according to the destination node’s
global lighting ID rather than using a hard coded peer ID as before.

With this change the method is now much more general as the prior
temporary hack has been removed.

networktest.go

@@ -79,6 +79,11 @@ type lightningNode struct {
 
 	nodeId int
 
+	// LightningId is the ID, or the sha256 of the node's identity public
+	// key. This field will only be populated once the node itself has been
+	// started via the start() method.
+	LightningID [32]byte
+
 	cmd     *exec.Cmd
 	pidFile string
 
@@ -181,6 +186,18 @@ func (l *lightningNode) start() error {
 
 	l.LightningClient = lnrpc.NewLightningClient(conn)
 
+	// Obtain the lnid of this node for quick identification purposes.
+	ctxb := context.Background()
+	info, err := l.GetInfo(ctxb, &lnrpc.GetInfoRequest{})
+	if err != nil {
+		return nil
+	}
+	lnID, err := hex.DecodeString(info.LightningId)
+	if err != nil {
+		return err
+	}
+	copy(l.LightningID[:], lnID)
+
 	return nil
 }
 
@@ -494,13 +511,10 @@ func (n *networkHarness) OpenChannel(ctx context.Context,
 	srcNode, destNode *lightningNode, amt btcutil.Amount,
 	numConfs uint32) (lnrpc.Lightning_OpenChannelClient, error) {
 
-	// TODO(roasbeef): should pass actual id instead, will fail if more
-	// connections added for Alice.
 	openReq := &lnrpc.OpenChannelRequest{
-		TargetPeerId:        1,
-		LocalFundingAmount:  int64(amt),
-		RemoteFundingAmount: 0,
-		NumConfs:            1,
+		TargetNode:         destNode.LightningID[:],
+		LocalFundingAmount: int64(amt),
+		NumConfs:           numConfs,
 	}
 	respStream, err := srcNode.OpenChannel(ctx, openReq)
 	if err != nil {