Added last missing signal replaceVectorLayer

This is only used by virtual layers, but it
might be handy for others too and now I can
start to remove all specialized source
select add methods from the datas source
manager dialog.

This is only the first step: next is looping
through the source select provider registry
to get all needed GUI elements for the dialog.

python/gui/qgsabstractdatasourcewidget.sip

@@ -90,6 +90,16 @@ Emitted when a vector layer has been selected for addition
  \param dataSourceType string (can be "file" or "database")
 %End
 
+    void replaceVectorLayer( const QString &oldId, const QString &source, const QString &name, const QString &provider );
+%Docstring
+ Emitted when a layer needs to be replaced
+ \param oldId old layer ID
+ \param source URI of the layer
+ \params name of the layer
+ \params provider key
+%End
+
+
     void progress( int, int );
 %Docstring
 Emitted when a progress dialog is shown by the provider dialog

src/gui/qgsabstractdatasourcewidget.h

@@ -93,6 +93,15 @@ class GUI_EXPORT QgsAbstractDataSourceWidget : public QDialog
      */
     void addVectorLayers( const QStringList &layerList, const QString &encoding, const QString &dataSourceType );
 
+    /** Emitted when a layer needs to be replaced
+     * \param oldId old layer ID
+     * \param source URI of the layer
+     * \params name of the layer
+     * \params provider key
+     */
+    void replaceVectorLayer( const QString &oldId, const QString &source, const QString &name, const QString &provider );
+
+
     //! Emitted when a progress dialog is shown by the provider dialog
     void progress( int, int );