xsfbs.sh: kill {,de}register_x_lib_dir_with_ld_so
xsfbs.sh: kill {,de}register_x_lib_dir_with_ld_so

libx11's postinst was the only post-sarge user, and it's gone now.

facboy/xserver-xorg-video-qxl,RsrchBoy/xserver-xorg-input-synaptics,philipn/xserver-xorg-input-synaptics,philipn/xserver-xorg-input-synaptics,facboy/xserver-xorg-video-qxl,philipn/xserver-xorg-input-synaptics,facboy/xserver-xorg-video-qxl,RsrchBoy/xserver-xorg-input-synaptics,facboy/xserver-xorg-video-qxl