Fix/cherry pick missing commits from slapos005
Somehow 3 commits from !35 (merged) got omitted from subsequent rebases: their changes are in 3.0.1+slapos005 but not in 3.0.1+slapos006 nor 3.0.1+slapos007.
These are what fixes buildout-testing/software-py2.cfg tests, so without these Python2 tests started failing again.