rebase -i: fix reword when using a terminal editor

We don't want to use output() on git-commit --amend when rewording the
commit message. This leads to confusion as the editor is run in a
subshell with it's output saved away, leaving the user with a seemingly
frozen terminal.

Fix by removing the output part.

Signed-off-by: Stephen Boyd <bebarino@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

git-rebase--interactive.sh

@@ -346,7 +346,7 @@ do_next () {
 		mark_action_done
 		pick_one $sha1 ||
 			die_with_patch $sha1 "Could not apply $sha1... $rest"
-		output git commit --amend
+		git commit --amend
 		;;
 	edit|e)
 		comment_for_reflog edit