Bug#867431: python3-hacking: incorrect dependencies

[Andreas Beckmann]

Followup-For: Bug #867431

I tried fixing this for jessie, too, but ${python3:Depends} contains a
spurious 'flake8' which does not exist on jessie.

(Also note that there is no pyflakes3 on jessie but pyflakes contains
the python3 bits, too.)


Andreas