swift: remove swift::iptables

swift::iptables seems to be an old, convoluted attempt of protecting
Swift boxes with iptables. Since they're unused for some time and
unlikely to ever be used in this form (esp. now that we have ferm),
remove them from the manifests to clean them up. This should be a noop.

Change-Id: I32b3c43d64ed970fb4bac1756bfcbdf9b48bcfcf