Fix for ONOS-5032 and ONOS-5034

Change-Id: Ib964252dd05754ce7069a7a82ccb1d1c29bfa978
diff --git a/core/api/src/main/java/org/onosproject/net/host/HostDescription.java b/core/api/src/main/java/org/onosproject/net/host/HostDescription.java
index ad423a3..dd25339 100644
--- a/core/api/src/main/java/org/onosproject/net/host/HostDescription.java
+++ b/core/api/src/main/java/org/onosproject/net/host/HostDescription.java
@@ -22,6 +22,7 @@
 import org.onlab.packet.IpAddress;
 import org.onlab.packet.MacAddress;
 import org.onlab.packet.VlanId;
+import org.onosproject.store.service.WallClockTimestamp;
 
 /**
  * Information describing host and its location.
@@ -55,4 +56,12 @@
      * @return host IP address
      */
     Set<IpAddress> ipAddress();
+
+    /**
+     * Returns the host recent updated Time.
+     * @return host last updated time.
+     */
+    default WallClockTimestamp timestamp() {
+        return null;
+    }
 }