Make iptables module build_rules accept protocol as an alias for proto
Make iptables module build_rules accept protocol as an alias for proto

The salt documentation mentions that **kwargs passed to an iptables
state such as iptables.append are passed to the iptables command as a
long command line option. This is not the case, as `--proto` is not an
iptables option, whereas `--protocol` is.

saltstack/salt,saltstack/salt,saltstack/salt,saltstack/salt,saltstack/salt