Want to overwrite redis::config::port by Hiera

I want to use the automatic parameter lookup.
http://docs.puppetlabs.com/hiera/1/puppet.html#automatic-parameter-lookup

## Sample usage:

~/src/our-boxen/config/hiera.yaml
```YAML
---
:backends:
  - yaml
:yaml:
  :datadir: '/opt/boxen/repo/hieradata'
:logger: console
:hierarchy:
  - common
```


~/src/our-boxen/hieradata/common.yaml
```YAML
---
redis::config::port: 7777777
```