intel_fbo: set gl_renderbuffer Depth field

Set the renderbuffer's Depth field to match the texture's
Depth when rendering to a texture.

Signed-off-by: Jordan Justen <jordan.l.justen@intel.com>
Reviewed-by: Paul Berry <stereotype441@gmail.com>
Reviewed-by: Eric Anholt <eric@anholt.net>

src/mesa/drivers/dri/intel/intel_fbo.c

@@ -494,6 +494,8 @@ intel_renderbuffer_update_wrapper(struct intel_context *intel,
    struct intel_mipmap_tree *mt = intel_image->mt;
    int level = image->Level;
 
+   rb->Depth = image->Depth;
+
    rb->AllocStorage = intel_nop_alloc_storage;
 
    intel_miptree_check_level_layer(mt, level, layer);