rails/rails — pull request #13859 by huoxito (2014-01-28 04:04:07+00:00)
Title: Let `unscope` ignore non Arel scope.where_values

It looks like `unscope` could be less agressive? So we could do thinks such as:

```ruby
User.where(name: 'Jamis').where("created_at > ?", 1.year.ago).unscope(where: [:name])
```

without raising an exception?