[gnome-shell] blur-effect: Fix crash when switching to ACTOR mode

[Georges Basile Stavracas Neto <gbsneto src gnome org>]

commit 463dcc6b931ac7d928c2ca98cc6aac81622cddbb
Author: Jonas Dreßler <verdre v0yd nl>
Date:   Mon Feb 10 15:20:51 2020 +0100

    blur-effect: Fix crash when switching to ACTOR mode
    
    The `clear_framebuffer()` function takes a CoglFramebuffer, not a
    FramebufferData object.
    
    https://gitlab.gnome.org/GNOME/gnome-shell/merge_requests/991

 src/shell-blur-effect.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
---
diff --git a/src/shell-blur-effect.c b/src/shell-blur-effect.c
index 2d49ffafec..4a2f8f782f 100644
--- a/src/shell-blur-effect.c
+++ b/src/shell-blur-effect.c
@@ -1082,7 +1082,7 @@ shell_blur_effect_set_mode (ShellBlurEffect *self,
   switch (mode)
     {
     case SHELL_BLUR_MODE_ACTOR:
-      clear_framebuffer (&self->background_fb);
+      clear_framebuffer (self->background_fb.framebuffer);
       break;
 
     case SHELL_BLUR_MODE_BACKGROUND: