Fix scaffold controller generator with namespace

[ceritium]

For example:

bundle exec rails g scaffold_controller Admin::Post title:string content:text --model-name=Post

It fixes the code generated by jbuilder. There is another fix on railties gem.

You can QA it modifying the Gemfile with:

gem "rails", github: "ceritium/rails", branch: "fix-scaffold-generator"
gem 'jbuilder', github: "ceritium/jbuilder", branch: "fix-scaffold-controller-namespace"

And run the following generators for example:

bundle exec rails g model title:string content:text
bundle exec rails g scaffold_controller Admin::Post title:string content:text --model-name=Post
rake test # or just run the generated tests

Then you can see the code and test the generated scaffold.