If rebase.stat is set to true, a diffstat should be displayed. If it is
not set, it should default to false. However, if it is explicitly set to
false (or other value), a diffstat is still displayed, which is probably
not what most users would expect. Show diffstat only if it is set
to true.
Signed-off-by: Martin von Zweigbergk <martin.von.zweigbergk@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>