Remove virtual method from class which shouldn't be subclassed

Author: nyalldawson

python/core/qgsproperty.sip

@@ -80,8 +80,6 @@ class QgsProperty
     };
 
     QgsProperty();
-    virtual ~QgsProperty();
-
     static QgsProperty fromExpression( const QString& expression, bool isActive = true );
     static QgsProperty fromField( const QString& fieldName, bool isActive = true );
     static QgsProperty fromValue( const QVariant& value, bool isActive = true );

src/core/qgsproperty.h

@@ -201,8 +201,6 @@ class CORE_EXPORT QgsProperty
      */
     QgsProperty();
 
-    virtual ~QgsProperty() = default;
-
     /**
      * Returns a new ExpressionBasedProperty created from the specified expression.
      */