Skip tst_QOpenGL::openGLPaintDevice() if wrong openGL version.

It seems that this case is failing on CI because OpenGL version,
so skip if OpenGL is not recent enough.

Task-number: QTBUG-24192
Change-Id: I543e7a092e5c107ee57cd9dce7dc5c890a0315cf
Reviewed-by: Friedemann Kleint <Friedemann.Kleint@nokia.com>
Reviewed-by: Samuel Rødal <samuel.rodal@nokia.com>

tests/auto/gui/qopengl/tst_qopengl.cpp

@@ -474,6 +474,9 @@ void tst_QOpenGL::openGLPaintDevice()
     QOpenGLContext ctx;
     ctx.create();
 
+    QSurfaceFormat format = ctx.format();
+    if (format.majorVersion() < 2)
+        QSKIP("This test requires at least OpenGL 2.0");
     ctx.makeCurrent(&window);
 
     QImage image(128, 128, QImage::Format_RGB32);