Potential fix to avoid multiple inserts

The `iptables -C` argument is not available on all distributions. A simple solution would be to issue a delete (`iptables -D`) prior to inserting the rule, this would make for a more compatible module.

http://www.netfilter.org/documentation/FAQ/netfilter-faq-3.html#ss3.18

PEP8 was complaining about the double hash (##). I removed one of the hashes to make PEP8 a little happier.