Add missing dependencies on concat and stdlib

There seems to be a missing dependency still in `params.pp`:

```puppet
  case $::is_pe {
    'false': {
      include puppet::params
      $ssl_dir = $puppet::params::puppet_ssldir
    }
    'true': {
      $ssl_dir = '/etc/puppetlabs/puppet/ssl'
    }
  }
```

Where should `puppet::params` come from?