git rebase allows you to specify a non-branch commit-ish as the "branch"
argument, which leaves HEAD detached when it's finished. This is
occasionally useful, and this patch brings the same functionality to git
rebase --interactive.
Signed-off-by: Dave Olszewski <cxreg@pobox.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>