Moved templates/rhel to template/redhat

The directory names under templates should be based on node[:platform], as discussed [here](http://docs.opscode.com/essentials_cookbook_templates.html#file-specificity).

The cookbook currently uses rhel, which is a platform_family, not a platform.  The correct platform should be "redhat".

```
# cat /etc/redhat-release 
Red Hat Enterprise Linux Server release 6.5 (Santiago)
# ohai
:
  "platform": "redhat",
  "platform_version": "6.5",
  "platform_family": "rhel",
:
```