CORD-60 Support dynamic vSG creation/deletion

We no longer need to configure /32 IP in interfaces.
SR will push a per-host route when discovering a host
with IP address(es) that does not belong to configured subnet.

Also includes:
- HostHandler refactoring

Change-Id: Ic1ad42d1ccdfee32be85f49e6fc94d9026000ffc
diff --git a/apps/segmentrouting/src/main/java/org/onosproject/segmentrouting/SegmentRoutingManager.java b/apps/segmentrouting/src/main/java/org/onosproject/segmentrouting/SegmentRoutingManager.java
index 5eec207..c18ae30 100644
--- a/apps/segmentrouting/src/main/java/org/onosproject/segmentrouting/SegmentRoutingManager.java
+++ b/apps/segmentrouting/src/main/java/org/onosproject/segmentrouting/SegmentRoutingManager.java
@@ -153,7 +153,7 @@
     protected ApplicationId appId;
     protected DeviceConfiguration deviceConfiguration = null;
 
-    private DefaultRoutingHandler defaultRoutingHandler = null;
+    protected DefaultRoutingHandler defaultRoutingHandler = null;
     private TunnelHandler tunnelHandler = null;
     private PolicyHandler policyHandler = null;
     private InternalPacketProcessor processor = null;