Simplifying yang_model usage.

Change-Id: I9a15522c1d081b8fa7480c744476fae0e9a94e88
diff --git a/bucklets/yang.bucklet b/bucklets/yang.bucklet
index 3d68180..797d520 100644
--- a/bucklets/yang.bucklet
+++ b/bucklets/yang.bucklet
@@ -7,6 +7,7 @@
     return ONOS_ARTIFACT_BASE + base_path.replace('/', '-') #TODO Unix-separator
 
 YANG_TOOLS = [
+    '//lib:CORE_DEPS',
     '//apps/yang:onos-apps-yang',
     '//lib:onos-yang-runtime',
 ]