fix progressbar in docker push
Add stubbed and commented "/etc/default/docker" to our deb package

This is to especially fix FPM 1.0+ complaining that we told it we have an /etc/default/docker "config file", but didn't actually include one.
Merge pull request #3427 from tianon/stub-deb-init-config

Add stubbed and commented "/etc/default/docker" to our deb package
Merge pull request #3287 from vieux/fix_progressbar_display_push

fix progressbar in docker push