rebase -i: do not fail when there is no commit to cherry-pick
In case there is no commit to apply (for example because you rebase to
upstream and all your local patches have been applied there), do not
fail. The non-interactive rebase already behaves that way.
Do this by introducing a new command, "noop", which is substituted for
an empty commit list, so that deleting the commit list can still abort
as before.
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Shawn O. Pearce <spearce@spearce.org>