Also, force rsc_control input to 0 when disarmed. This prevents condition where AP_MotorsHeli can receive a rotor speed command greater than zero while disarmed, which was causing the ColYaw function to move the rudder servo. These two changes are somewhat tied together as it required changing the arming_check to check the RSC_Control not desired_speed from AP_MotorsHeli.
Removed potentially endless loop caused by start_logging calling
Log_Write_Startup which called should_log which could then call
start_logging.
Moved disarm event logging above motors disarm so it is logged
