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/src/main/java/org/onosproject/segmentrouting/SegmentRoutingManager.java b/src/main/java/org/onosproject/segmentrouting/SegmentRoutingManager.java
index 0e23a26..12c52bf 100644
--- a/src/main/java/org/onosproject/segmentrouting/SegmentRoutingManager.java
+++ b/src/main/java/org/onosproject/segmentrouting/SegmentRoutingManager.java
@@ -370,6 +370,8 @@
                                       "forceUnprovision", "true");
         compCfgService.preSetProperty("org.onosproject.routeservice.store.RouteStoreImpl",
                                       "distributed", "true");
+        compCfgService.preSetProperty("org.onosproject.provider.host.impl.HostLocationProvider",
+                                      "multihomingEnabled", "true");
 
         processor = new InternalPacketProcessor();
         linkListener = new InternalLinkListener();