e comp - set e_comp to null on shutdown so others dont access junk
e comp - set e_comp to null on shutdown so others dont access junk

e backlight was accessing e_comp implicitly during shutdown and comp
is shut down before backlight (that is correct as comp relies on
backlight). this fixes that

@fix

tasn/enlightenment,rvandegrift/e,tasn/enlightenment,tasn/enlightenment,rvandegrift/e,rvandegrift/e