AP_InertialNav: remove dead get_hagl method

libraries/AP_InertialNav/AP_InertialNav_NavEKF.cpp

@@ -144,20 +144,6 @@ float AP_InertialNav_NavEKF::get_altitude() const
     return _relpos_cm.z;
 }
 
-/**
- * getHgtAboveGnd - get latest height above ground level estimate in cm and a validity flag
- *
- * @return
- */
-bool AP_InertialNav_NavEKF::get_hagl(float &height) const
-{
-    // true when estimate is valid
-    bool valid = _ahrs_ekf.get_hagl(height);
-    // convert height from m to cm
-    height *= 100.0f;
-    return valid;
-}
-
 /**
  * get_velocity_z - returns the current climbrate.
  *

libraries/AP_InertialNav/AP_InertialNav_NavEKF.h

@@ -88,12 +88,6 @@ public:
      */
     float       get_altitude() const;
 
-    /**
-     * getHgtAboveGnd - get latest altitude estimate above ground level in centimetres and validity flag
-     * @return
-     */
-    bool       get_hagl(float &hagl) const;
-
     /**
      * get_velocity_z - returns the current climbrate.
      *