tests: Mount source tree into container read-only

The release workflow now builds the dist tarball by itself, so the
container test can be completely read-only. This avoids unintended
*.pyc/egg-info clutter on the host.

Author: martinpitt

tests/run

@@ -8,4 +8,4 @@ else
     RUNC="sudo docker"
 fi
 
-$RUNC run --interactive --rm --volume `pwd`:/source --workdir /source docker.io/"$IMAGE" /bin/sh tests/run-${IMAGE%:*}
+$RUNC run --interactive --rm --volume `pwd`:/source:ro --workdir /source docker.io/"$IMAGE" /bin/sh tests/run-${IMAGE%:*}

tests/run-ubuntu

@@ -35,6 +35,3 @@ wait
 
 ./setup.py sdist
 EOF
-
-# copy release tarball to outside; for bind mounts only
-[ ! -d /source ] || cp -r /tmp/source/dist /source/