Return version from iptables --version

    CLI Example:

    .. code-block:: bash

        salt '*' iptables.version

        IPv6:
        salt '*' iptables.version family=ipv6

def version(family='ipv4'):
    '''
    Return version from iptables --version

    CLI Example:

    .. code-block:: bash

        salt '*' iptables.version

        IPv6:
        salt '*' iptables.version family=ipv6
    '''
    cmd = '{0} --version' . format(_iptables_cmd(family))
    out = __salt__['cmd.run'](cmd).split()
    return out[1]