do not return when x11 damage event returns no rects
do not return when x11 damage event returns no rects

ensure first_damage flag is set in all cases

tizenorg/platform.upstream.enlightenment,tasn/enlightenment,tizenorg/platform.upstream.enlightenment,tizenorg/platform.upstream.enlightenment,rvandegrift/e,rvandegrift/e,tasn/enlightenment,rvandegrift/e,tasn/enlightenment