Fixing #207 - only try to install iptables-ipv6 package if CentOS 6

[vladionescu]

Description

See issue #207, the iptables-ipv6 package is trying to be installed anytime the following 3 conditions are true: ipv6 enabled, iptables enabled, not Debian. The problem is this package only exists for CentOS 6, all other distros bundle v6 functionality in the standard iptables package. Trying to install iptables-ipv6 on other distros causes the chef run to fail. This fixes that, only installing it if we're on CentOS 6.

This has been tested working on Fedora 28. I haven't tested on any other distros, and don't have the time to do so. This PR is provided as-is.

Issues Resolved

#207

Check List

• [ ] All tests pass. See https://github.com/chef-cookbooks/community_cookbook_documentation/blob/master/TESTING.MD
• [ ] New functionality includes testing.
• [ ] New functionality has been documented in the README if applicable
• [ ] All commits have been signed for the Developer Certificate of Origin. See https://github.com/chef-cookbooks/community_cookbook_documentation/blob/master/CONTRIBUTING.MD

[martinb3]

Hi there; it looks like this needs a Signed-off-by in the commit still.

[vladionescu]

Sorry about that, I got confused and expected it to be signed off by a project owner. All done!

[damacus]

I don't think we should accept this anymore, given that CentOS 6 is now EOL