Compute/setup fog coordinates even if vertex program is enabled.

Only when fog's enabled, of course.
In the usual case, this is just a pass-through operation.
diff --git a/src/mesa/tnl/t_pipeline.c b/src/mesa/tnl/t_pipeline.c
index 2a0ed88..357ef1e 100644
--- a/src/mesa/tnl/t_pipeline.c
+++ b/src/mesa/tnl/t_pipeline.c
@@ -199,11 +199,11 @@
    &_tnl_vertex_transform_stage,
    &_tnl_normal_transform_stage,
    &_tnl_lighting_stage,
-   &_tnl_fog_coordinate_stage,
    &_tnl_texgen_stage,
    &_tnl_texture_transform_stage,
    &_tnl_point_attenuation_stage,
    &_tnl_vertex_program_stage, 
+   &_tnl_fog_coordinate_stage,
    &_tnl_render_stage,
    NULL 
 };