AP_Soaring: fixed filter constructor calls

fixes valgrind error from copy of filter objects on the stack

libraries/AP_Soaring/AP_Soaring.cpp

@@ -149,9 +149,6 @@ SoaringController::SoaringController(AP_SpdHgtControl &spdHgt, const AP_Vehicle:
     _throttle_suppressed(true)
 {
     AP_Param::setup_object_defaults(this, var_info);
-
-    _position_x_filter = LowPassFilter<float>(1.0/60.0);
-    _position_y_filter = LowPassFilter<float>(1.0/60.0);
 }
 
 void SoaringController::get_target(Location &wp)

libraries/AP_Soaring/AP_Soaring.h

@@ -56,8 +56,8 @@ class SoaringController {
 
     float _thermalability;
 
-    LowPassFilter<float> _position_x_filter;
-    LowPassFilter<float> _position_y_filter;
+    LowPassFilter<float> _position_x_filter{1/60.0};
+    LowPassFilter<float> _position_y_filter{1/60.0};
 
 protected:
     AP_Int8 soar_active;

libraries/AP_Soaring/Variometer.cpp

@@ -9,9 +9,6 @@ Manages the estimation of aircraft total energy, drag and vertical air velocity.
 Variometer::Variometer(const AP_Vehicle::FixedWing &parms) :
     _aparm(parms)
 {
-    _climb_filter = LowPassFilter<float>(1.0/60.0);
-
-    _vdot_filter2 = LowPassFilter<float>(1.0f/60.0f);
 }
 
 void Variometer::update(const float thermal_bank, const float polar_K, const float polar_Cd0, const float polar_B)

libraries/AP_Soaring/Variometer.h

@@ -32,9 +32,8 @@ class Variometer {
     AverageFilterFloat_Size5 _sp_filter;
 
     // low pass filter @ 30s time constant
-    LowPassFilter<float> _climb_filter;
-
-    LowPassFilter<float> _vdot_filter2;
+    LowPassFilter<float> _climb_filter{1/60.0};
+    LowPassFilter<float> _vdot_filter2{1/60.0};
 
 public:
     Variometer(const AP_Vehicle::FixedWing &parms);