fix sip error

git-svn-id: http://svn.osgeo.org/qgis/trunk/qgis@11834 c8812cc2-4d05-0410-92ff-de0c093fc19c

Author: jef

python/core/qgsmaplayer.sip

@@ -254,7 +254,7 @@ public:
 
     /** Get the QImage used for caching render operations
      * @note This method was added in QGIS 1.4 **/
-    QImage * cacheImage() { return mpCacheImage; }
+    QImage *cacheImage();
     /** Set the QImage used for caching render operations 
      * @note This method was added in QGIS 1.4 **/
     void setCacheImage( QImage * thepImage );