[nostory] fix CI

Change-Id: I5cc4df090aa1804e846c2dbee7b4d060417079b3

gz3d/utils/Gruntfile.js

@@ -115,7 +115,8 @@ module.exports = function(grunt) {
       },
       dist: {
         options: {
-          ignoreEmpty: true,
+          verbose: true,
+          force: true
         },
         files: {
           src: ['../build/gz3d.js']