In vnet CLI, separates virutal port creation and binding operations.
Original usage with specifiying a phyiscal port is also in supporting.

Changes.
1. vnet-create-port allow to create virtual port
   without a specific virtual port
2. vnet-bind-port command is added to newly bind or to update
3. Virtual binding point is changed from Port to ConnectPoint.

Change-Id: I4c8f9a2b9b2786ba519ead3559d7f005390fee86
diff --git a/cli/src/main/java/org/onosproject/cli/net/vnet/VirtualPortListCommand.java b/cli/src/main/java/org/onosproject/cli/net/vnet/VirtualPortListCommand.java
index 0f1c99e..a35d22a 100644
--- a/cli/src/main/java/org/onosproject/cli/net/vnet/VirtualPortListCommand.java
+++ b/cli/src/main/java/org/onosproject/cli/net/vnet/VirtualPortListCommand.java
@@ -62,7 +62,8 @@
         VirtualNetworkService service = get(VirtualNetworkService.class);
 
         List<VirtualPort> virtualPorts = new ArrayList<>();
-        virtualPorts.addAll(service.getVirtualPorts(NetworkId.networkId(networkId), DeviceId.deviceId(deviceId)));
+        virtualPorts.addAll(service.getVirtualPorts(NetworkId.networkId(networkId),
+                                                    DeviceId.deviceId(deviceId)));
         Collections.sort(virtualPorts, Comparators.VIRTUAL_PORT_COMPARATOR);
         return virtualPorts;
     }
@@ -73,7 +74,12 @@
      * @param virtualPort virtual port
      */
     private void printVirtualPort(VirtualPort virtualPort) {
-        print(FMT_VIRTUAL_PORT, virtualPort.number(),
-              virtualPort.realizedBy().element().id(), virtualPort.realizedBy().number());
+        if (virtualPort.realizedBy() == null) {
+            print(FMT_VIRTUAL_PORT, virtualPort.number(), "None", "None");
+        } else {
+            print(FMT_VIRTUAL_PORT, virtualPort.number(),
+                  virtualPort.realizedBy().deviceId(),
+                  virtualPort.realizedBy().port());
+        }
     }
 }