AP_Parachute: removed create() method for objects

See discussion here:

  https://github.com/ArduPilot/ardupilot/issues/7331

we were getting some uninitialised variables. While it only showed up in
AP_SbusOut, it means we can't be sure it won't happen on other objects,
so safest to remove the approach

Thanks to assistance from Lucas, Peter and Francisco

libraries/AP_Parachute/AP_Parachute.h

@@ -25,12 +25,18 @@
 class AP_Parachute {
 
 public:
-    static AP_Parachute create(AP_Relay &relay) {
+    /// Constructor
-        return AP_Parachute{relay};
+    AP_Parachute(AP_Relay &relay)
+        : _relay(relay)
+        , _release_time(0)
+        , _release_initiated(false)
+        , _release_in_progress(false)
+        , _released(false)
+    {
+        // setup parameter defaults
+        AP_Param::setup_object_defaults(this, var_info);
     }
 
-    constexpr AP_Parachute(AP_Parachute &&other) = default;
-
     /* Do not allow copies */
     AP_Parachute(const AP_Parachute &other) = delete;
     AP_Parachute &operator=(const AP_Parachute&) = delete;
@@ -63,18 +69,6 @@ public:
     static const struct AP_Param::GroupInfo        var_info[];
 
 private:
-    /// Constructor
-    AP_Parachute(AP_Relay &relay)
-        : _relay(relay)
-        , _release_time(0)
-        , _release_initiated(false)
-        , _release_in_progress(false)
-        , _released(false)
-    {
-        // setup parameter defaults
-        AP_Param::setup_object_defaults(this, var_info);
-    }
-
     // Parameters
     AP_Int8     _enabled;       // 1 if parachute release is enabled
     AP_Int8     _release_type;  // 0:Servo,1:Relay

libraries/AP_Parachute/examples/AP_Parachute_test/AP_Parachute_test.cpp

@@ -19,10 +19,10 @@ void loop();
 const AP_HAL::HAL& hal = AP_HAL::get_HAL();
 
 // Relay
-static AP_Relay relay = AP_Relay::create();
+static AP_Relay relay;
 
 // Parachute
-static AP_Parachute parachute = AP_Parachute::create(relay);
+static AP_Parachute parachute{relay};
 
 void setup()
 {