Bug: Rails 4 order hashes fail inside a has_many.

In Rails 4, if you give a has_many an order using a hash to specify the sort direction, it's misinterpreted:

```ruby
class Person < ActiveRecord::Base
  has_many :articles_with_order, lambda { order :title => :desc },
    :class_name => 'Article'
end
```

```ruby
Person.first.articles_with_order.to_sql
 # => SELECT "articles".* FROM "articles"  WHERE "articles"."person_id" = ?  ORDER BY "title"."desc"
```

A failing spec is attached. It demonstrates the issue, though it probably needs a little rewriting.