AC_AttitudeControl_Heli: Add initialization of _flags_heli members

libraries/AC_AttitudeControl/AC_AttitudeControl_Heli.h

@@ -34,6 +34,14 @@ public:
         yaw_acceleration_feedforward_filter(AC_ATTITUDE_HELI_RATE_Y_AFF_FILTER)
         {
             AP_Param::setup_object_defaults(this, var_info);
+
+            // initialise flags
+            _flags_heli.limit_roll = false;
+            _flags_heli.limit_pitch = false;
+            _flags_heli.limit_yaw = false;
+            _flags_heli.leaky_i = true;
+            _flags_heli.flybar_passthrough = false;
+            _flags_heli.tail_passthrough = false;
         }
 
     // passthrough_bf_roll_pitch_rate_yaw - roll and pitch are passed through directly, body-frame rate target for yaw