This took a long time to track down, but this will allow rolling deploys or tasks with Capistrano 2.x.

task :rolling, roles: :web do 
  find_servers_for_task(current_task).each do |s|
    puts roles[:web].clear()
    server s.host, :web
    puts "Deploying to #{s.host}..."
    find_and_execute_task('deploy')
  end
end

Ref: https://groups.google.com/forum/#!topic/capistrano/H-tizsMN2Tk