firewall: store iptables chains in OrderedDict

circle/firewall/fw.py

 import re
 import re
 import logging
 import logging
+from collections import OrderedDict
 from netaddr import IPAddress, AddrFormatError
 from netaddr import IPAddress, AddrFormatError
 from datetime import datetime, timedelta
 from datetime import datetime, timedelta
 from itertools import product
 from itertools import product
@@ -18,7 +19,7 @@ logger = logging.getLogger(__name__)
 class BuildFirewall:
 class BuildFirewall:
 
 
     def __init__(self):
     def __init__(self):
-        self.chains = {}
+        self.chains = OrderedDict()
 
 
     def add_rules(self, *args, **kwargs):
     def add_rules(self, *args, **kwargs):
         for chain_name, ipt_rule in kwargs.items():
         for chain_name, ipt_rule in kwargs.items():