Add Nfdc functionality to enable working with FaceID rather than FaceURI exclusively

refs: #5130

Change-Id: I1b7ca1846cafdde8e959663ba53d5bd50b455b39
diff --git a/examples/wifi/wifi_ping.py b/examples/wifi/wifi_ping.py
index 6ba0531..16fd62d 100644
--- a/examples/wifi/wifi_ping.py
+++ b/examples/wifi/wifi_ping.py
@@ -65,8 +65,8 @@
 
     info("Starting pingserver...")
     NDNPing.startPingServer(b, "/example")
-    Nfdc.createFace(a, b.IP())
-    Nfdc.registerRoute(a, "/example", b.IP())
+    faceID = Nfdc.createFace(a, b.IP())
+    Nfdc.registerRoute(a, "/example", faceID)
 
     info("Starting ping...")
     NDNPing.ping(a, "/example", nPings=10)