The images seem to have been broken starting with 12e12a3, but the
removal of Maven support from grpc-java also broke them further.
SSH handling no longer uses $HOME as it does not agree with /etc/passwd
in older docker versions[1] and prevented SSH from seeing the config
file.
Some effort was also made to reduce the image sizes by removing
temporary files.
1. https://github.com/docker/docker/issues/2968
Donna Dionne