vnc stopped using the copyrect pseudo encoding in 2017, in commit
50628d34 ("cirrus/vnc: zap bitblit support from console code.")
So we can drop the now unused copyrect feature bit.

Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
Message-id: 20201208115737.18581-5-kraxel@redhat.com