vbo: return VP_NONE from get_program_mode() if running fixed-func vertex program

If we're running a vertex program to emulated fixed-function, we still need
to treat vertex arrays/attributes as if we're in fixed-function mode.

This should probably be back-ported to Mesa 7.5 after a bit more testing.

src/mesa/vbo/vbo_context.h

@@ -102,6 +102,8 @@ get_program_mode( GLcontext *ctx )
 {
    if (!ctx->VertexProgram._Current)
       return VP_NONE;
+   else if (ctx->VertexProgram._Current == ctx->VertexProgram._TnlProgram)
+      return VP_NONE;
    else if (ctx->VertexProgram._Current->IsNVProgram)
       return VP_NV;
    else