BGP support default IPV4 unicast capability.

Change-Id: Id9ad101e82a9148ddf029fdcf6404173a9574539
diff --git a/protocols/bgp/bgpio/src/main/java/org/onosproject/bgpio/util/Constants.java b/protocols/bgp/bgpio/src/main/java/org/onosproject/bgpio/util/Constants.java
index 4c8c7df..33fdfc8 100644
--- a/protocols/bgp/bgpio/src/main/java/org/onosproject/bgpio/util/Constants.java
+++ b/protocols/bgp/bgpio/src/main/java/org/onosproject/bgpio/util/Constants.java
@@ -34,7 +34,8 @@
     public static final short AFI_VALUE = 16388;
     public static final byte VPN_SAFI_VALUE = (byte) 0x80;
     public static final byte SAFI_VALUE = 71;
-
+    public static final short AFI_IPV4_UNICAST = 1;
+    public static final byte SAFI_IPV4_UNICAST = 1;
     public static final short AFI_FLOWSPEC_VALUE = 1;
     public static final byte SAFI_FLOWSPEC_VALUE = (byte) 133;
     public static final byte VPN_SAFI_FLOWSPEC_VALUE = (byte) 134;