Create rspec-system tests for RedHat family

Provides the necessary nodset configurations and examples
on how to run the tests on RedHat family systems.

Using CentOS 6.4 as a representative for RedHat family systems,
as there is a box available from the puppetlabs Vagrant boxes
repository with the same Virtualbox version requirements as the
existing Ubuntu Precise one:

http://puppet-vagrant-boxes.puppetlabs.com

This is needed to test solutions for bugs 1264959 and 1264916.

There is a circular dependency issue between those bugs and this:
Cannot test the solutions to those bugs without this patch, but without
solutions to those tests the rspec-system tests for RedHat family
systems won't run. To have only running code committed, this should
only be merged together with the other patches.

Change-Id: I2093635034ca78b7fb6dbfd950cf35af8a03bc6f
Closes-Bug: 1253211
Related-Bug: 1264959
Related-Bug: 1264916
Fixes Bug: "yum repo don't work in CentOS 6.4"

Removing curly braces around the the basearch parameter which
lead to parsing issues.

Fixing additional issues with yum repo configuration and
adapting the CI test.

Locally verified this with RS_SET=two-centos-64-x64.
While it would be preferable to verify it via gerritexec,
all of the CI except ceph_repo_spec.pp fail.
This will be handled with subsquent patches.

Change-Id: Ia99e20dab8c496cc3becec77acbe38003c6d7779
Closes-Bug: 1264959
Partially-Bug: 1264916