Purge internal map variables by leveraging persistent store

Change-Id: If347de18803a6f84a220e1ffdee26b9e1c28634b
diff --git a/apps/openstacknetworking/app/src/main/java/org/onosproject/openstacknetworking/impl/DefaultInstancePort.java b/apps/openstacknetworking/app/src/main/java/org/onosproject/openstacknetworking/impl/DefaultInstancePort.java
index 0a53885..23dc684 100644
--- a/apps/openstacknetworking/app/src/main/java/org/onosproject/openstacknetworking/impl/DefaultInstancePort.java
+++ b/apps/openstacknetworking/app/src/main/java/org/onosproject/openstacknetworking/impl/DefaultInstancePort.java
@@ -179,8 +179,8 @@
     }
 
     @Override
-    public InstancePort updatePrevData(DeviceId oldDeviceId,
-                                       PortNumber oldPortNumber) {
+    public InstancePort updatePrevLocation(DeviceId oldDeviceId,
+                                           PortNumber oldPortNumber) {
         return new Builder()
                 .networkId(networkId)
                 .portId(portId)