[ONOS-3664] Update the bug: the ports command for restful can not get
external port.

Change-Id: Icad4ff9647f08f174f197b3dd2378ceef22cafe3
diff --git a/apps/vtn/vtnrsc/src/main/java/org/onosproject/vtnrsc/cli/virtualport/VirtualPortExGwUpdateCommand.java b/apps/vtn/vtnrsc/src/main/java/org/onosproject/vtnrsc/cli/virtualport/VirtualPortExGwUpdateCommand.java
index 837d8c4..f0e31f6 100644
--- a/apps/vtn/vtnrsc/src/main/java/org/onosproject/vtnrsc/cli/virtualport/VirtualPortExGwUpdateCommand.java
+++ b/apps/vtn/vtnrsc/src/main/java/org/onosproject/vtnrsc/cli/virtualport/VirtualPortExGwUpdateCommand.java
@@ -23,6 +23,7 @@
 import org.onlab.packet.IpAddress;
 import org.onlab.packet.MacAddress;
 import org.onosproject.cli.AbstractShellCommand;
+import org.onosproject.net.DeviceId;
 import org.onosproject.vtnrsc.BindingHostId;
 import org.onosproject.vtnrsc.DefaultVirtualPort;
 import org.onosproject.vtnrsc.FixedIp;
@@ -86,7 +87,7 @@
                                                          VirtualPort.State.DOWN,
                                                          MacAddress.valueOf(macAddress),
                                                          subnet.tenantId(),
-                                                         null,
+                                                         DeviceId.deviceId(""),
                                                          Sets.newHashSet(fixedGwIp),
                                                          BindingHostId.bindingHostId(""),
                                                          Sets.newHashSet(),