Bug#934899: lintian tries and fail to unpack non ar archives

[Felix Lechner <felix.lechner@lease-up.com>]

Hi,

According to 'git bisect' I introduced this bug when I provided a
defective implementation of `safe_qx` based on IO::Async in commit
39cd0295by, and unwittingly fixed it in commit 0d8ed5fa. The fix was
committed a few hours before the bug was filed. It was just-in-time
development!

The earlier version of 'safe_qx' raised an exception when 'ar'
returned with an error in `collection/ar-info` here :

    https://salsa.debian.org/lintian/lintian/blob/master/collection/ar-info#L67

Now the error is ignored again, in a brittle way, by parsing the
output and adding to the list of archives presumably non-sensical
entries that are discarded later. My preference would be to apply the
merge request on top of it.

I am just not sure that the /^current ar archive/ regex is broad
enough. Any ideas?

Kind regards
Felix