AP_Compass: zero some more variables in constructor and init

libraries/AP_Compass/AP_Compass_AK8963.cpp

@@ -286,7 +286,11 @@ bool AP_Compass_AK8963_MPU9250::read_raw()
 
 AP_Compass_AK8963::AP_Compass_AK8963(Compass &compass) : 
     AP_Compass_Backend(compass),    
-    _backend(NULL)
+    _backend(NULL),
+    _initialised(false),
+    _state(CONVERSION),
+    _last_update_timestamp(0),
+    _last_accum_time(0)
 {
     _initialised = false;
     _mag_x_accum =_mag_y_accum = _mag_z_accum = 0;

libraries/AP_Compass/AP_Compass_HIL.cpp

@@ -27,7 +27,8 @@ extern const AP_HAL::HAL& hal;
 
 // constructor
 AP_Compass_HIL::AP_Compass_HIL(Compass &compass):
-    AP_Compass_Backend(compass)    
+    AP_Compass_Backend(compass),
+    _compass_instance(0)
 {
     _compass._setup_earth_field();
 }

libraries/AP_Compass/AP_Compass_HMC5843.cpp

@@ -60,7 +60,16 @@ extern const AP_HAL::HAL& hal;
 // constructor
 AP_Compass_HMC5843::AP_Compass_HMC5843(Compass &compass):
     AP_Compass_Backend(compass),
+    _i2c_sem(NULL),
+    _mag_x(0),
+    _mag_y(0),
+    _mag_z(0),
+    _mag_x_accum(0),
+    _mag_y_accum(0),
+    _mag_z_accum(0),
     _accum_count(0),
+    _last_accum_time(0),
+    _compass_instance(0),
     _retry_time(0),
     _product_id(0)
 {}

libraries/AP_Compass/AP_Compass_PX4.cpp

@@ -43,8 +43,10 @@ extern const AP_HAL::HAL& hal;
 
 // constructor
 AP_Compass_PX4::AP_Compass_PX4(Compass &compass):
-    AP_Compass_Backend(compass)
-{}
+    AP_Compass_Backend(compass),
+    _num_sensors(0)
+{
+}
 
 // detect the sensor
 AP_Compass_Backend *AP_Compass_PX4::detect(Compass &compass)
@@ -91,7 +93,7 @@ bool AP_Compass_PX4::init(void)
 
         // remember if the compass is external
         set_external(_instance[i], ioctl(_mag_fd[i], MAGIOCGEXTERNAL, 0) > 0);
-        _count[0] = 0;
+        _count[i] = 0;
         _sum[i].zero();
     }