bucklet for yang based OSGI libraries

Change-Id: Ieeef6357250c4e74e9c78310a65c809b3edd102b
diff --git a/buck-tools/default.defs b/buck-tools/default.defs
index 9c72161..0c55630 100644
--- a/buck-tools/default.defs
+++ b/buck-tools/default.defs
@@ -2,6 +2,7 @@
 include_defs('//bucklets/maven_jar.bucklet')
 include_defs('//bucklets/onos.bucklet')
 include_defs('//bucklets/onos_app.bucklet')
+include_defs('//bucklets/yang.bucklet')
 include_defs('//bucklets/remote_jar.bucklet')
 
 BASE_DEPS = [