CentOS 5.6 integration test fails

The CentOS AMI that we use in integration tests fails to validate the www.opscode.com certificate. Maybe they have renewed it and the image has an ancient CA bundle?

Anyway we should upgrade to 5.9 and add new 6.x. CentOS offers 6.3 AMIs that could be used, but they seem to have iptables rules that make the apache test to fail. But that's easy to fix.