t3404: demonstrate CHERRY_PICK_HEAD bug
When rev-list's --cherry option does not detect that a patch has already
been applied upstream, an interactive rebase would offer to reapply it and
consequently stop at that patch with a failure, mentioning that the diff
is empty.
Traditionally, a `git rebase --continue` simply skips the commit in such a
situation.
However, as pointed out by Gábor Szeder, this leaves a CHERRY_PICK_HEAD
behind, making the Git prompt believe that a cherry pick is still going
on. This commit adds a test case demonstrating this bug.
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>