compositor-x11: implement x11_output_destroy()
compositor-x11: implement x11_output_destroy()

Signed-off-by: Pekka Paalanen <6c0263d81461c956d504307112a4ce25eaacc3d1@gmail.com>

jonnylamb/weston,Tarnyko/weston-xdg_surface_present,Fantu/compositor-spice,xorgy/weston,sir-murray/weston,mchalupa/weston,eyolfson/weston,mchalupa/weston,Gnurou/weston,krezovic/weston,udoprog/weston,udoprog/weston,giucam/weston,giucam/weston,sir-murray/weston,Fantu/compositor-spice,Fantu/compositor-spice,Tarnyko/weston-xdg_surface_present,xorgy/weston,krezovic/weston,kwm81/weston,eyolfson/weston,jonnylamb/weston,Gnurou/weston,kwm81/weston