backlight: fix backlight_path memory leak
backlight: fix backlight_path memory leak

Signed-off-by: U. Artie Eoff <32aece0d55055227b44d04b7d0051cf3d04ee871@intel.com>

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