As done in recipes/stripe.rb, let's assign variables early:

```ruby
detach_timeout = node['rs-storage']['device']['detach_timeout'].to_i
nickname = node['rs-storage']['device']['nickname']
size = node['rs-storage']['device']['volume_size'].to_i
```
Noticed I also added `size`.  Let's set this and us it replacing the 3 times we use the node attribute.