This commit simply removes an extra comma that was added in
52fced8d7a to prevent issues with older
versions of IE. I found this when running grunt to prepare the 3.6.4
release:
```
Running "jshint:all" (jshint) task
assets/js/admin/meta-boxes-order.js
413 | user_email : user_email,
^ Extra comma. (it breaks older versions of IE)
```
We might want to add jshint to the pre-commit hook and to Travis.
3d12ec4ae2