Merge branch 'vp/show-ref-verify-head'

"git show-ref HEAD" used with "--verify" because the user is not interested in seeing refs/remotes/origin/HEAD, and used with "--head" because the user does not want HEAD to be filtered out, i.e. "git show-ref --head --verify HEAD", did not work as expected. * vp/show-ref-verify-head: show-ref: remove a stale comment show-ref: remove dead `if (verify)' check show-ref: detect dangling refs under --verify as well show-ref: move --quiet handling into show_one() show-ref: allow -d to work with --verify show-ref: accept HEAD with --verify