Reformat some BUILD files according to the buildifier guidelines

Change-Id: I8aa599f89fc14296275193475e50eb8f27b4bf0a
diff --git a/models/ietf/BUILD b/models/ietf/BUILD
index 9197c54..cdb559a 100644
--- a/models/ietf/BUILD
+++ b/models/ietf/BUILD
@@ -1,7 +1,7 @@
 load("//tools/build/bazel:yang.bzl", "yang_model")
 
-yang_model (
+yang_model(
     app_name = "org.onosproject.models.ietf",
-    title = "IETF YANG Models",
     custom_registrator = False,
+    title = "IETF YANG Models",
 )