commitextras: fix on Python 3 by using sysstrs for __dict__ ops
I'm dubious of the __dict__ shenanigans in use here, but lack the
enthusiasm for figuring out why that was done right now.
# skip-blame just some r prefixes
Differential Revision: https://phab.mercurial-scm.org/D2435
FROM ubuntu:__CODENAME__
RUN apt-get update && apt-get install -y \
build-essential \
debhelper \
devscripts \
dh-python \
less \
python \
python-all-dev \
python-docutils \
unzip \
zip