Bug#983435: Regarding the backup/restore function

[bugsgrid+deb at gmail.com]

Regarding the backup/restore function
in the commit bb3205709aa9f83e1c8cb91e7f6f9f110d41b34e,
for me it seems bringing in more critical dangers than the safety it provides.

The logic is too error prone, it relies on on_exit() absolutely never
duped by any fork()'s,
meaning it's requiring absolutely every fork() in the entire code to be patched.
And there is no safeguard against misfiring of restore_backup_on_exit().
It itself is "just irrevocably removing them as the first action,"
even if there is nothing to be restored.
Oh well.

I bet it's better to set onhold on grub for now...