Symbian: disable OpenVG as default on Symbian emulator builds

Symbian emulator shows QML applications badly when OpenVG graphics
system is used. This fix ignores OpenVG graphics system default
configuration when built for emulator target.

Task-number: ou1cimx1#1005008
Change-Id: I63fb89c5074e03fd582bfbbccca55f33473285c3
Reviewed-by: Pauli Järvinen <[email protected]>
Reviewed-by: Shane Kearns <[email protected]>
(cherry picked from commit 8393c80)
Reviewed-by: Pasi Pentikäinen <[email protected]>

Author: Pasi Pentikainen

src/gui/painting/qgraphicssystemfactory.cpp

@@ -65,7 +65,7 @@ QGraphicsSystem *QGraphicsSystemFactory::create(const QString& key)
     if (system.isEmpty()) {
         system = QLatin1String("opengl");
     }
-#elif defined (QT_GRAPHICSSYSTEM_OPENVG)
+#elif defined (QT_GRAPHICSSYSTEM_OPENVG) && !defined(Q_CC_NOKIAX86)
     if (system.isEmpty()) {
         system = QLatin1String("openvg");
     }