When splitting a repository, running `git rebase -i --root` to reword
the initial commit, Git dies with
BUG: sequencer.c:795: root commit without message.
Signed-off-by: Todd Zullinger <tmz@pobox.com> Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de> Signed-off-by: Junio C Hamano <gitster@pobox.com>