The difference in the sum, has to do with an arbitrary order that can occur
when tar'ing hardlinks. The first file encountered pointing to the inode wins
and has it's Size recorded. Then following files that may have the same inode,
then have their LinkName point to the first file's Name, and their Size is 0.
WIP to fix ti https://github.com/vbatts/docker/compare/vbatts-archive_sort