python3 flake: fix CsNetfilter.py

```
../debian/opt/cloud/bin/cs/CsNetfilter.py:226:13: E117 over-indented
../debian/opt/cloud/bin/cs/CsNetfilter.py:233:180: E501 line too long (197 > 179 characters)
../debian/opt/cloud/bin/cs/CsNetfilter.py:241:14: E201 whitespace after '{'
../debian/opt/cloud/bin/cs/CsNetfilter.py:242:14: E201 whitespace after '{'
../debian/opt/cloud/bin/cs/CsNetfilter.py:247:18: E201 whitespace after '{'
../debian/opt/cloud/bin/cs/CsNetfilter.py:247:74: E202 whitespace before '}'
../debian/opt/cloud/bin/cs/CsNetfilter.py:248:18: E201 whitespace after '{'
```

systemvm/debian/opt/cloud/bin/cs/CsNetfilter.py

@@ -223,29 +223,30 @@ def delete(self, rule):
         self.rules[:] = [x for x in self.rules if not x == rule]
 
     def add_ip6_chain(self, address_family, table, chain, hook, action):
-            chain_policy = ""
-            if hook:
-                chain_policy = "type filter hook %s priority 0;" % hook
-            if chain_policy and action:
-                chain_policy = "%s policy %s;" % (chain_policy, action)
-            CsHelper.execute("nft add chain %s %s %s '{ %s }'" % (address_family, table, chain, chain_policy))
-            if hook == "input" or hook == "output":
-                CsHelper.execute("nft add rule %s %s %s icmpv6 type { echo-request, echo-reply, nd-neighbor-solicit, nd-router-advert, nd-neighbor-advert } accept" % (address_family, table, chain))
+        chain_policy = ""
+        if hook:
+            chain_policy = "type filter hook %s priority 0;" % hook
+        if chain_policy and action:
+            chain_policy = "%s policy %s;" % (chain_policy, action)
+        CsHelper.execute("nft add chain %s %s %s '{ %s }'" % (address_family, table, chain, chain_policy))
+        if hook == "input" or hook == "output":
+            CsHelper.execute("nft add rule %s %s %s icmpv6 type { echo-request, echo-reply, \
+                nd-neighbor-solicit, nd-router-advert, nd-neighbor-advert } accept" % (address_family, table, chain))
 
     def apply_ip6_rules(self, rules, type):
         if len(rules) == 0:
             return
         address_family = 'ip6'
         table = 'ip6_firewall'
         default_chains = [
-            { "chain": "fw_input", "hook": "input", "action": "drop"},
-            { "chain": "fw_forward", "hook": "forward", "action": "accept"}
+            {"chain": "fw_input", "hook": "input", "action": "drop"},
+            {"chain": "fw_forward", "hook": "forward", "action": "accept"}
         ]
         if type == "acl":
             table = 'ip6_acl'
             default_chains = [
-                { "chain": "acl_input", "hook": "input", "action": "drop" },
-                { "chain": "acl_forward", "hook": "forward", "action": "accept"}
+                {"chain": "acl_input", "hook": "input", "action": "drop"},
+                {"chain": "acl_forward", "hook": "forward", "action": "accept"}
             ]
         CsHelper.execute("nft add table %s %s" % (address_family, table))
         for chain in default_chains: