Implement L2 load balancer support in XConnectManager

Change-Id: Ib310a1dde72db38abb60273ce66b5f72768bf4ca
diff --git a/app/BUILD b/app/BUILD
index 70c3589..de9beab 100644
--- a/app/BUILD
+++ b/app/BUILD
@@ -4,6 +4,7 @@
     "//apps/route-service/api:onos-apps-route-service-api",
     "//apps/mcast/api:onos-apps-mcast-api",
     "//apps/mcast/cli:onos-apps-mcast-cli",
+    "//apps/l2lb:onos-apps-l2lb",
 ]
 
 TEST_DEPS = TEST_ADAPTERS + [