I18n common attributes and Translate.attribute_name

I have locale's file:
```yaml
en:
  # Attributes names common to most models
  attributes:
    name: 'NAME'
  activerecord:
    attributes:
      brand:
```

I get a model's attribute's translation:
```ruby
1.9.3p125 :011 > Brand.human_attribute_name(:name)
 => "NAME"
```

I have a problem when using ```sort_link```. For example, 
```ruby
sort_link @search, :name, Brand.human_attribute_name(:name) # Translation — NAME. That is ok.
sort_link @search, :name # Translation — Name. Default humanize attribute's translation.
```

I added a new locale's path for translate common attributes to ```self.attribute_name```.

```sort_link``` give the correct translation now:
```ruby
sort_link @search, :name # Translation — NAME.
```