'git rebase' uses the full onto sha1 for the reflog message whereas 'git
rebase -i' uses the short sha1. This is not only inconsistent, but can
lead to problems when the reflog is inspected at a later time at which
that abbreviation may have become ambiguous.
Make 'rebase -i' use the full onto sha1, as well.
Signed-off-by: Michael J Gruber <git@drmicha.warpmail.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>