- Initially install docker 1.11.1 for docker image loading. 1.11.1
  doesn't require docker service running in target filesystem root
  to load images. The latest version supports so is 1.12.2-0.
- After all docker images have been loaded, upgrade docker engine to
  docker ce 18.09.0~3-0. Also due to the complicity of chroot
  installation. Removing docker-engine.prerm is needed for successful
  uninstall of version 1.11.1.
- New version deprecated docker daemon sub-command, using dockerd
  instead. (Deprecated 1.13.0 and removed in 17.12).
- dockerd -H fd:// doesn't work. Change to -H unix://.

Signed-off-by: Ying Xie <ying.xie@microsoft.com>

Signed-off-by: Ying Xie <ying.xie@microsoft.com>