BUCKify XosClient app to fix buck build

Change-Id: I5c9e6127ef3c00b79d12163fc82d4137ad00b407
diff --git a/BUCK b/BUCK
index 3336d39..5eda6bf 100644
--- a/BUCK
+++ b/BUCK
@@ -119,6 +119,7 @@
     '//apps/faultmanagement:onos-apps-faultmanagement-oar',
     '//apps/openstacknode:onos-apps-openstacknode-oar',
     '//apps/cpman/app:onos-apps-cpman-app-oar',
+    '//apps/xosclient:onos-apps-xosclient-oar',
 ]
 
 APP_JARS = [