Bug#920691: lintian gets stuck collecting info after failed objdump-info

[Felix Lechner]

I think this is related to Perl update 5.28.1-3. Shortly afterward, I
had the problem raised in #916087, which also showed up with
IO::Async. Files did not close properly. It seemed processes were
spawned differently. Copies of open file descriptors survived in
spawned processes, and I was unable to close files open for writing.
Perhaps the note helps someone.