red_worker.c: fix calling set_client_capabilities when it is unsupported by qemu
red_worker.c: fix calling set_client_capabilities when it is unsupported by qemu

The erroneous call was in handle_dev_start.
This patch also fixes not calling set_client_capabilities when the
qxl major_version is > 3.

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