routing: track unifiedPolicyEdge

Preparation so that we can have the inbound fee available
in addition to the outgoing policy.

routing/router_test.go

@@ -2450,8 +2450,8 @@ func TestFindPathFeeWeighting(t *testing.T) {
 	if len(path) != 1 {
 		t.Fatalf("expected path length of 1, instead was: %v", len(path))
 	}
-	if path[0].ToNodePubKey() != ctx.aliases["luoji"] {
-		t.Fatalf("wrong node: %v", path[0].ToNodePubKey())
+	if path[0].policy.ToNodePubKey() != ctx.aliases["luoji"] {
+		t.Fatalf("wrong node: %v", path[0].policy.ToNodePubKey())
 	}
 }