Remove iptables >1.4.11 specific functionality

Scientific Linux 6 (and likely other similar distributions such as CentOS 6) ship with iptables 1.4.7, which doesn't support the -C flag. In order to use iptables 1.4.11 (the first version that supports "-C"), we would not only have to upgrade iptables, but would also have to update our kernel version.

Looking at examples of how other systems are handling this, Saltstack actually parses the help document to figure out if "--check" is present, and then either uses it (if present), or does something similar to this patch (if absent): https://github.com/saltstack/salt/blob/d50fdcb456ab69407610c5fa2abab68605af8084/salt/modules/iptables.py#L462

@thockin This is a continuation of #1979, now with ~100% more actually working, less bash, and a bit more testability.

I'm getting the same results for the e2e tests for this and master (using vagrant to run it): basic.sh and guestbook.sh passing and the others failing.