Bug#870393: autopkgtest setup fails strangely with arch-qualified sources.list

[Martin Pitt]

Control: tag -1 pending

Hello Steve!

Steve Langasek [2017-08-01  9:06 -0700]:
> This can be resolved with a two-pass sed script, first ignoring the [] field
> and then applying the rest of the rules to extract the series name.

Thanks for the patch! Applied to git (I also grabbed stgraber's change from
4.3ubuntu1).

Pitti