Update statusline only when changed to reduce cpu usage.
commit 2512c0403f ("statusline: implement per-account status") updates
the status irrespective of whether the statusline changed or not. This
can lead to high cpu usage that can be avoided.
Reported-by: Jens Grassel <jens@wegtam.com>
Reported-by: inwit <inwit@sindominio.net>
Signed-off-by: Koni Marti <koni.marti@gmail.com>
Acked-by: Robin Jarry <robin@jarry.cc>