[Pkg-haskell-maintainers] Bug#773768: jenkins reproduces this issue

[Helmut Grohne]

Control: reopen -1
Control: found -1 7.8.4-2

I am sad to tell that jenkins.debian.net reproduces this issue in one of
its jobs. You can find the full log at:

https://jenkins.debian.net/job/reproducible_setup_schroot_unstable_debbindiff/77/console

Mattia, could cause the job to print its apt invocation line and copy
the failing apt invocation to this bug log?

Helmut