Fixed OpenGL ES 3 incompatibility.

Fixed surface format initialization to use OpenGL ES 2.0 on OpenGL ES 3.0 capable devices.

Change-Id: I2bb77294af47211f4b72c4d06a5d4c794be134cd
Reviewed-by: Pasi Keränen <pasi.keranen@digia.com>

src/canvas3d.cpp

@@ -314,6 +314,10 @@ CanvasContext *Canvas::getContext(const QString &type, const QVariantMap &option
         }
 
         QSurfaceFormat surfaceFormat = m_glContextQt->format();
+#if defined(QT_OPENGL_ES_2)
+        surfaceFormat.setMajorVersion(2);
+        surfaceFormat.setMinorVersion(0);
+#endif
         surfaceFormat.setSwapBehavior(QSurfaceFormat::SingleBuffer);
         surfaceFormat.setSwapInterval(0);