add Mac and hostname to POST url

This commit is to handle the case:
We receive a DELETE to delete a vBNG, and then receive
a POST with the same private IP address to create vBNG.

At this moment, if the old vCPE is not down, and the new
vCPE is not up yet, onos will use the host with old
vCPE mac address to create the intent, which is not
correct, and hard to solve. Since onos does not know
the host in the system is old vCPE or new vCPE.

Thus, we change to ask XOS to post us host MAC
and hostname together with the private IP address.

Change-Id: I011924aada589ea81d80a479aefa41753fa2e223
diff --git a/apps/virtualbng/src/main/java/org/onosproject/virtualbng/VbngService.java b/apps/virtualbng/src/main/java/org/onosproject/virtualbng/VbngService.java
index c27f86f..051469e 100644
--- a/apps/virtualbng/src/main/java/org/onosproject/virtualbng/VbngService.java
+++ b/apps/virtualbng/src/main/java/org/onosproject/virtualbng/VbngService.java
@@ -16,6 +16,7 @@
 package org.onosproject.virtualbng;
 
 import org.onlab.packet.IpAddress;
+import org.onlab.packet.MacAddress;
 
 /**
  * Provides service of the virtual BNG.
@@ -31,10 +32,13 @@
      * </p>
      *
      * @param privateIpAddress the private IP address
+     * @param hostMacAddress the MAC address for the IP address
+     * @param hostName the host name for the IP address
      * @return the public address if a virtual BGN is successfully created,
      *         otherwise return null
      */
-    IpAddress createVbng(IpAddress privateIpAddress);
+    IpAddress createVbng(IpAddress privateIpAddress, MacAddress hostMacAddress,
+                         String hostName);
 
     /**
      * Deletes a virtual BNG.