server/red_worker: on_new_display_channel_client: push ack, cleanup
server/red_worker: on_new_display_channel_client: push ack, cleanup

small cleanup patch, only functional change is sending a set ack message.

dezelin/spice,mathslinux/spice,alon/spice-server,mathslinux/spice,alon/spice-server,mathslinux/spice,elmarco/spice,mathslinux/spice,fgouget/spice,dezelin/spice,fgouget/spice,mathslinux/spice,Fantu/spice,alon/spice-server,Fantu/spice,dezelin/spice,ya-mouse/spice,dezelin/spice,freedesktop-unofficial-mirror/spice__spice,elmarco/spice,freedesktop-unofficial-mirror/spice__spice,Fantu/spice,SPICE/spice,freedesktop-unofficial-mirror/spice__spice,elmarco/spice,alon/spice-server,fgouget/spice,SPICE/spice,alon/spice-server,fgouget/spice,freedesktop-unofficial-mirror/spice__spice,freedesktop-unofficial-mirror/spice__spice,ya-mouse/spice,Fantu/spice,elmarco/spice,SPICE/spice,dezelin/spice,ya-mouse/spice,elmarco/spice