compositor-openwfd: Fix event handler return type
compositor-openwfd: Fix event handler return type

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