Fixes this compiler error:
In file included from ../../ArduCopter/sensors.cpp:1:
In file included from ../../ArduCopter/Copter.h:195:
../../ArduCopter/mode.h:1291:9: fatal error: declaration shadows a variable in the global namespace [-Wshadow]
AUTO, // after A and B defined, pilot toggle the switch from one side to the other, vehicle flies autonomously
^
../../ArduCopter/defines.h:38:5: note: previous declaration is here
AUTO = 3, // fully automatic waypoint control using mission commands
^
1 error generated.