add virtual destructor

fix warning: delete called on 'QgsEditorWidgetAutoConfPlugin' that is abstract but has non-virtual destructor

python/gui/editorwidgets/core/qgseditorwidgetautoconf.sip.in

@@ -21,6 +21,8 @@ Base class for plugins allowing to pick automatically a widget type for editing
 %End
   public:
 
+    virtual ~QgsEditorWidgetAutoConfPlugin();
+
     virtual QgsEditorWidgetSetup editorWidgetSetup( const QgsVectorLayer *vl, const QString &fieldName, int &score /Out/ ) const = 0;
 %Docstring
 Typical scores are:

src/gui/editorwidgets/core/qgseditorwidgetautoconf.h

@@ -33,6 +33,8 @@ class GUI_EXPORT QgsEditorWidgetAutoConfPlugin
 {
   public:
 
+    virtual ~QgsEditorWidgetAutoConfPlugin() {}
+
     /**
      * Typical scores are:
      *   * 0: no matching type found.