Fixes hydroponics not producing food if there is no mutmod in the nutrient

Removed process() from machinery/lights as it was not being used.

git-svn-id: http://tgstation13.googlecode.com/svn/trunk@4020 316c924e-a436-60f5-8080-3fe189b3f50e

code/modules/power/lighting.dm

@@ -563,12 +563,14 @@
 // timed process
 // use power
 
+/*
 #define LIGHTING_POWER_FACTOR 20		//20W per unit luminosity
 
 /obj/machinery/light/process()
 	return
 //	if(on)
 //		use_power(luminosity * LIGHTING_POWER_FACTOR, LIGHT)
+*/
 
 // called when area power state changes
 /obj/machinery/light/power_change()