eliminate the OGR message about not being able to open a read-only

.shp file (if it is read-only, qgis then tries to open it read-only,
so the OGR error message is unnecessary).


git-svn-id: http://svn.osgeo.org/qgis/trunk/qgis@5617 c8812cc2-4d05-0410-92ff-de0c093fc19c

Author: g_j_m

src/providers/ogr/qgsogrprovider.cpp

@@ -88,8 +88,13 @@ QgsOgrProvider::QgsOgrProvider(QString const & uri)
 
   QgsDebugMsg("Data source uri is " + uri);
 
-  // try to open for update
+  // try to open for update, but disable error messages to avoid a
+  // message if the file is read only, because we cope with that
+  // ourselves.
+  CPLPushErrorHandler(&CPLQuietErrorHandler);
   ogrDataSource = OGRSFDriverRegistrar::Open(QFile::encodeName(uri).constData(), TRUE, &ogrDriver);
+  CPLPopErrorHandler();
+
   if(ogrDataSource == NULL)
   {
     // try to open read-only