Allow module to manage "/etc/ssh/ssh_known_hosts" file.

Allow module to manage "/etc/ssh/ssh_known_hosts" file.

    ssh::resource::known_hosts { 'global-known-hosts':
      hosts               =>  'github.com,bitbucket.org',
      user                =>  'root',
      root                =>  '/etc/ssh',
      known_hosts         =>  '/etc/ssh/ssh_known_hosts',
      known_hosts_mode    =>  '0644',
    }