sequencer (rebase -i): remove CHERRY_PICK_HEAD when no longer needed

The scripted version of the interactive rebase already does that.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

sequencer.c

@@ -1832,8 +1832,13 @@ static int commit_staged_changes(struct replay_opts *opts)
 
 	if (has_unstaged_changes(1))
 		return error(_("cannot rebase: You have unstaged changes."));
-	if (!has_uncommitted_changes(0))
+	if (!has_uncommitted_changes(0)) {
+		const char *cherry_pick_head = git_path("CHERRY_PICK_HEAD");
+
+		if (file_exists(cherry_pick_head) && unlink(cherry_pick_head))
+			return error(_("could not remove CHERRY_PICK_HEAD"));
 		return 0;
+	}
 
 	if (file_exists(rebase_path_amend())) {
 		struct strbuf rev = STRBUF_INIT;