Isolate IETF models in OpenConfig to own bundle

Change-Id: I15fff358582dd7b361d015c2d30c981a703fd1be
diff --git a/models/ietf/BUCK b/models/ietf/BUCK
new file mode 100644
index 0000000..6cc9d15
--- /dev/null
+++ b/models/ietf/BUCK
@@ -0,0 +1,7 @@
+
+yang_model (
+  app_name = 'org.onosproject.models.ietf',
+  title = 'IETF YANG Models',
+  custom_registrator = False,
+  deps = [ '//lib:CORE_DEPS' ]
+)