Fix mod::prefork dependencies

[nanliu]

A dependency on the package resolves the following error:
"Error: /Stage[main]/Apache::Mod::Prefork/File_line[/etc/sysconfig/httpd
prefork enable]: Could not evaluate: No such file or directory -
/etc/sysconfig/httpd"

[agt-the-walker]

Hello,
I can reproduce the above error with the following configuration on Arch Linux (x86_64):

$ VBoxHeadless --version | tail -1; vagrant --version; librarian-puppet version
4.2.12_OSEr84980
Vagrant version 1.2.2
librarian-puppet v0.9.9


$ egrep -v '^( *#|$)' Vagrantfile 
Vagrant.configure("2") do |config|
  config.vm.box = "centos59-64"
  config.vm.box_url = "http://puppet-vagrant-boxes.puppetlabs.com/centos-59-x64-vbox4210.box"
  config.vm.provision :puppet do |puppet|
    puppet.manifests_path = "manifests"
    puppet.module_path = "modules"
  end
end


$ cat manifests/default.pp 
class { 'apache': }


$ cat Puppetfile
forge "http://forge.puppetlabs.com"

mod 'apache',
  :git => 'git://github.com/puppetlabs/puppetlabs-apache.git'


$ librarian-puppet install; cat Puppetfile.lock
FORGE
  remote: http://forge.puppetlabs.com
  specs:
    puppetlabs/firewall (0.3.0)
    puppetlabs/stdlib (3.2.0)
    ripienaar/concat (0.2.0)

GIT
  remote: git://github.com/puppetlabs/puppetlabs-apache.git
  ref: master
  sha: 3a7f0b90b3dfadcd64dee14d1f437391021dbd38
  specs:
    apache (0.6.0)
      puppetlabs/firewall (>= 0.0.4)
      puppetlabs/stdlib (>= 2.2.1)
      ripienaar/concat (>= 0.2.0)

DEPENDENCIES
  apache (>= 0)


$ vagrant up
[...]
Running Puppet with default.pp...
Warning: Config file /etc/puppet/hiera.yaml not found, using Hiera defaults
Warning: Scope(Class[Apache]): Class['apache'] parameter purge_vdir is deprecated in favor of purge_configs
Notice: /Stage[main]/Concat::Setup/File[/var/lib/puppet/concat]/ensure: created
Notice: /Stage[main]/Concat::Setup/File[/var/lib/puppet/concat/bin]/ensure: created
Notice: /Stage[main]/Concat::Setup/File[/var/lib/puppet/concat/bin/concatfragments.sh]/ensure: defined content as '{md5}256169ee61115a6b717b2844d2ea3128'
Error: /Stage[main]/Apache::Mod::Prefork/File_line[/etc/sysconfig/httpd prefork enable]: Could not evaluate: No such file or directory - /etc/sysconfig/httpd
[...]

More details upon request. Thanks for your time.