ruby-dev not installed on webapp node

i thought i fixed this with #7834 (closed), but still, ruby-dev is not installed on the webapp node in a multinode setup. see https://jenkins.leap.se/job/platform_develop/195/console

maybe we didn't stepped into this because i set up the ci build nodes with my varac/jessie vagrant image, which is quite minimal and we always had it pre-installed before, i don't know.

But looking at how we try to install the ruby-dev package, this never could have worked:

--- site_config/manifests ‹develop› » cat ruby.pp 
# install ruby, rubygems and bundler
# configure ruby settings common to all servers
class site_config::ruby {
  Class[Ruby] -> Class[rubygems] -> Class[bundler::install]
  class { '::ruby': }
  class { 'bundler::install': install_method => 'package' }
  include rubygems
}


--- site_config/manifests ‹develop› » cat ruby/dev.pp 
# install ruby dev packages needed for building some gems
class site_config::ruby::dev inherits site_config::ruby {
  Class['::ruby'] {
    install_dev  => true
  }
  # building gems locally probably requires build-essential and gcc:
  include site_config::packages::build_essential
}

ruby itself is a parameterized class, and "parameters cannot get overridden":https://projects.puppetlabs.com/issues/9259

(from redmine: created on 2016-01-22, closed on 2016-01-26, relates #7834 (closed))