Comment 0 for bug 2019022

The Bionic DEP8 tests for iptables are in bad shape[1], even in the migration-reference/0 run.

There are two types of failures:
a) some commands have an exit status of 1 when called with the -h (for help) option, which is what some tests do
b) iptables-compat-save (and its IPv6 counterpart) also exit with status 1, even when there are chains/tables to save

I'll propose:
a) grep the help output instead of relying on the exit status
b) call the command with the -d (dump) option. That doesn't exit 0 in the success case, and actually dumps data when there are tables to do so

1. https://autopkgtest.ubuntu.com/packages/i/iptables/bionic/amd64