Rearrange the code related to GL_ARB_occlusion_object to generalize query
objects for future types of queries.
diff --git a/src/mesa/drivers/common/driverfuncs.c b/src/mesa/drivers/common/driverfuncs.c
index 4a8ea31..c027123 100644
--- a/src/mesa/drivers/common/driverfuncs.c
+++ b/src/mesa/drivers/common/driverfuncs.c
@@ -209,6 +209,10 @@
    driver->FramebufferRenderbuffer = _mesa_framebuffer_renderbuffer;
 #endif
 
+   /* query objects */
+   driver->BeginQuery = NULL;
+   driver->EndQuery = NULL;
+
    /* T&L stuff */
    driver->NeedValidate = GL_FALSE;
    driver->ValidateTnlModule = NULL;