[mutter/gnome-3-28] cogl-auto-texture: Avoid a double-free crash

[Marco Trevisan <marcotrevi src gnome org>]

commit 6a6d477d719d36851b8cb46c34300fff4b3e4c86
Author: Daniel van Vugt <daniel van vugt canonical com>
Date:   Thu Oct 11 06:49:22 2018 +0000

    cogl-auto-texture: Avoid a double-free crash
    
    If texture allocation fails (e.g. on an old GPU with size limit 2048)
    then `cogl_texture_new_with_size` was trying to use the same CoglError
    twice. The second time was after it had already been freed.
    
    Bug reported and fix provided by Gert van de Kraats.
    
    https://launchpad.net/bugs/1790525
    
    
    (cherry picked from commit d21478b0f0163b0688abe065a7009b33453d0d00)

 cogl/cogl/deprecated/cogl-auto-texture.c | 1 +
 1 file changed, 1 insertion(+)
---
diff --git a/cogl/cogl/deprecated/cogl-auto-texture.c b/cogl/cogl/deprecated/cogl-auto-texture.c
index 29a5f73ef..fe52e1575 100644
--- a/cogl/cogl/deprecated/cogl-auto-texture.c
+++ b/cogl/cogl/deprecated/cogl-auto-texture.c
@@ -94,6 +94,7 @@ cogl_texture_new_with_size (unsigned int width,
       if (!cogl_texture_allocate (tex, &skip_error))
         {
           cogl_error_free (skip_error);
+          skip_error = NULL;
           cogl_object_unref (tex);
           tex = NULL;
         }