iptables mod: add missing space after comma & add parens around tuple for clarity

************* Module salt.modules.iptables
salt/modules/iptables.py:84: [C0324(no-space-after-comma), build_rule] Comma not followed by a space
for ignore in '__id__', 'fun', 'table', 'chain','__env__','__sls__','order':
^^
Merge pull request #7956 from hulu/iptables-fix

iptables mod: add missing space after comma & add parens around tuple