Test commits/branches/IDs by using git show-ref instead of git log.
Test commits/branches/IDs by using git show-ref instead of git log.

This allows us to avoid the problem with changes to branch name formatting
in the git-log %d format option.

cjs-cynic-net/git-commit-filetree,cjs-cynic-net/git-commit-filetree,cjs-cynic-net/git-commit-filetree