using subnet as lease/range selection criteria in DHCP Relay App, addressed review comments

Change-Id: Id2a81faa00592df4ede33f6679c2ba2dd8fb2293
diff --git a/apps/dhcprelay/src/main/resources/dhcp-relay.json b/apps/dhcprelay/src/main/resources/dhcp-relay.json
index f94f15c..616c4ab 100644
--- a/apps/dhcprelay/src/main/resources/dhcp-relay.json
+++ b/apps/dhcprelay/src/main/resources/dhcp-relay.json
@@ -2,7 +2,9 @@
   "apps": {
     "org.onosproject.dhcp-relay" : {
       "dhcprelay" : {
-        "dhcpserverConnectPoint": "of:0000000000000002/2"
+        "dhcpserverConnectPoint": "of:0000000000000002/2",
+        "serverip": "172.168.10.2",
+        "servermac": "d2:70:98:90:8c:44"
       }
     }
   }