compositor: check version before calling wl_output_send_scale()
compositor: check version before calling wl_output_send_scale()

Signed-off-by: Derek Foreman <2f97e0f0bc172406aab8ccd42dab54c95bab8759@osg.samsung.com>
Reviewed-by: Pekka Paalanen <0f6ae7001e34c37b02fb2c1c2573ddf8f442136a@collabora.co.uk>

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