packaging: don't write files for templatized Dockerfiles
Now that Docker image building is implemented in Python and we
can perform template substitution in memory, we don't need to
write out produced Dockerfiles to disk.
Differential Revision: https://phab.mercurial-scm.org/D3760
FROM ubuntu:%CODENAME%
RUN groupadd -g 1000 build && \
useradd -u 1000 -g 1000 -s /bin/bash -d /build -m build
RUN apt-get update && apt-get install -y \
build-essential \
debhelper \
devscripts \
dh-python \
less \
python \
python-all-dev \
python-docutils \
unzip \
zip