x11: Remove destroy listener when X11 window is destroyed
x11: Remove destroy listener when X11 window is destroyed

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