APM_Control: cleanup some coverity warnings

libraries/APM_Control/AP_AutoTune.cpp

@@ -70,10 +70,12 @@ extern const AP_HAL::HAL& hal;
 AP_AutoTune::AP_AutoTune(ATGains &_gains, ATType _type,
                          const AP_Vehicle::FixedWing &parms,
                          DataFlash_Class &_dataflash) :
+    running(false),
     current(_gains),
     type(_type),
     aparm(parms),
-    dataflash(_dataflash)
+    dataflash(_dataflash),
+    saturated_surfaces(false)
 {}
 
 #if CONFIG_HAL_BOARD == HAL_BOARD_SITL

libraries/APM_Control/AP_AutoTune.h

@@ -77,17 +77,17 @@ private:
     ATGains next_save;
 
     // time when we last saved
-    uint32_t last_save_ms;
+    uint32_t last_save_ms = 0;
 
     // the demanded/achieved state
     enum ATState {DEMAND_UNSATURATED,
                   DEMAND_UNDER_POS, 
                   DEMAND_OVER_POS,
                   DEMAND_UNDER_NEG,
-                  DEMAND_OVER_NEG} state;
+                  DEMAND_OVER_NEG} state = DEMAND_UNSATURATED;
 
     // when we entered the current state
-    uint32_t state_enter_ms;
+    uint32_t state_enter_ms = 0;
 
     void check_save(void);
     void check_state_exit(uint32_t state_time_ms);