Fixed inproper declration of a struct when in fact its a class

git-svn-id: http://svn.osgeo.org/qgis/trunk/qgis@7225 c8812cc2-4d05-0410-92ff-de0c093fc19c

src/core/raster/qgsrasterlayer.h

@@ -196,7 +196,7 @@ class QgsRect;
 class QgsRasterBandStats;
 class QgsRasterPyramid;
 class QgsRasterLayerProperties;
-class QgsRasterViewPort;
+struct QgsRasterViewPort;
 class QImage;
 class QPixmap;