Fix problem when destroying a non-paranoid has_one association

Given these models:

```ruby
class User < ActiveRecord::Base
  acts_as_paranoid
  has_one :preference, dependent: :destroy
end

class Preference < ActiveRecord::Base
  belongs_to :user
end
```

It will raise error when performing `really_destroy!` for a `User` record.

```ruby
user.really_destroy!
#=> NameError: undefined local variable or method `touch_paranoia_column' for #<Preference:0x007fd>
```