BUCKify XosClient app to fix buck build

Change-Id: I5c9e6127ef3c00b79d12163fc82d4137ad00b407
diff --git a/BUCK b/BUCK
index d898be9..cd0e8cb 100644
--- a/BUCK
+++ b/BUCK
@@ -11,6 +11,7 @@
     '//core/store/serializers:onos-core-serializers',
     '//apps/openstackinterface/api:onos-apps-openstackinterface-api',
     '//apps/dhcp/api:onos-apps-dhcp-api',
+    '//apps/xosclient:onos-apps-xosclient',
     '//protocols/ovsdb/api:onos-ovsdb-api',
     '//protocols/ovsdb/rfc:onos-ovsdb-rfc',
 ]
@@ -36,4 +37,5 @@
     included_bundles = BUNDLES,
     excluded_bundles = EXCLUDED_BUNDLES,
     description = 'APIs for interacting with the CORD VTN application.',
+    required_apps = [ 'org.onosproject.xosclient' ],
 )