Fails to install older Erlang version

[xhujerr]

If you have two Erlang versions in your repositories it fails to install the older one. In my case the new one is Erlang 18.1. The erlang package obsoletes the older packages (of same name). My workaround is:

  if $erlang_exclude_version {
    package {'erlang':
      ensure => $erlang_version,
      install_options => {'--exclude'=> "erlang-${erlang_exclude_version}"},
    }
  } else {
    package {'erlang':
      ensure => $erlang_version,
    }
  }

From hieradata I supply erlang_exclude_version=18.1 so the resulting yum command looks like:
yum install erlang-R14B --exclude erlang-18.1