CORD-1416 Implement multi-homing probing in HostLocationProvider

Also include following refactoring
    - Refactor the way we generate ARP probe
    - Remove some unused code

Change-Id: I96b1c47bd5731b7b38ef4d19a941d231b5d0054c
diff --git a/core/net/src/main/java/org/onosproject/net/host/impl/HostManager.java b/core/net/src/main/java/org/onosproject/net/host/impl/HostManager.java
index cda9e04..f6c5856 100644
--- a/core/net/src/main/java/org/onosproject/net/host/impl/HostManager.java
+++ b/core/net/src/main/java/org/onosproject/net/host/impl/HostManager.java
@@ -455,6 +455,16 @@
             store.removeLocation(hostId, location);
         }
 
+        @Override
+        public MacAddress addPendingHostLocation(HostId hostId, HostLocation hostLocation) {
+            return store.addPendingHostLocation(hostId, hostLocation);
+        }
+
+        @Override
+        public void removePendingHostLocation(MacAddress probeMac) {
+            store.removePendingHostLocation(probeMac);
+        }
+
         private boolean allowedToChange(HostId hostId) {
             // Disallow removing inexistent host or host provided by others
             Host host = store.getHost(hostId);