made ctstate default to [] and evaluation conditional on the list being popoulated

lib/ansible/modules/extras/system/iptables.py

@@ -262,6 +262,7 @@ def construct_rule(params):
     append_param(rule, params['to_ports'], '--to-ports', False)
     append_comm(rule, params['comment'])
     append_param(rule, params['comment'], '--comment', False)
+    if params['ctstate']:
         append_conntrack(rule, params['ctstate'])
         append_param(rule, ','.join(params['ctstate']), '--ctstate', False)
     return rule