plataformatec/simple_form — pull request #1086 by kaichen (2014-06-19 08:35:17+00:00)
Title: remove warning of label_text method in wrapper, when replace html label tag to other tag

Sometime we would use other html tag(span ex.) to replace label html tag in label
component in custom wrapper:

```ruby
config.wrappers :custom_wrapper, tag: 'div', class: 'form-group control-group' do |b|
b.wrapper tag: 'span', class: "control-label" do |l|
l.use :label_text
end
b.wrapper :controls, tag: 'div', class: 'controls' do |i|
i.use :input
end
end
```

After that [breaking wrappers api change](https://github.com/plataformatec/simple_form/pull/997),
this usage will cause deprecated wraning. This patch solves the problem.