./docker-package.sh silently fails

Without Docker installed, `./docker-package.sh` appeared to run to completion however old blobs were installed. `.build.log` said that Docker was not installed. After installing Docker and adding myself to the group, `./docker-package.sh` finally installed new blobs.

Start with ./docker-package.sh and inspect .build.log while reproducing the run without Docker installed. Verify that the script does not appear successful or install old blobs when Docker is unavailable, and confirm the behavior after Docker is installed and usable.

Written by the indexing model from the issue text.