Copter: correct comment on deprecated switch option

ArduCopter/defines.h

@@ -41,7 +41,7 @@ enum aux_sw_func {
     AUXSW_CAMERA_TRIGGER =       9, // trigger camera servo or relay
     AUXSW_RANGEFINDER =         10, // allow enabling or disabling rangefinder in flight which helps avoid surface tracking when you are far above the ground
     AUXSW_FENCE =               11, // allow enabling or disabling fence in flight
-    AUXSW_RESETTOARMEDYAW =     12, // deprecated.  changes yaw to be same as when quad was armed
+    AUXSW_RESETTOARMEDYAW =     12, // UNUSED
     AUXSW_SUPERSIMPLE_MODE =    13, // change to simple mode in middle, super simple at top
     AUXSW_ACRO_TRAINER =        14, // low = disabled, middle = leveled, high = leveled and limited
     AUXSW_SPRAYER =             15, // enable/disable the crop sprayer