ido insists on trying to save ido.last

[trentbuck]

When I invoke Emacs with

    sudo emacs

instead of

    sudo -H emacs

Emacs runs with root priviledges, but $HOME is still set to /home/twb.
/home is an NFS partition with root_squash on, so emacs does not have
write permission to ~/.emacs.d/.  When using ido, this results in an
emacs that cannot be closed with C-x C-c or kill-emacs:

    Save file /home/twb/.emacs.d/ido.last? (y, n, !, ., q, C-r, d or C-h) n
    Modified buffers exist; exit anyway? (yes or no) yes
    File ido.last is write-protected; try to save anyway? (yes or no) no

    Debugger entered--Lisp error: (error "Attempt to save to a file which you 
aren't allowed to write")
      signal(error ("Attempt to save to a file which you aren't allowed to 
write"))
      error("Attempt to save to a file which you aren't allowed to write")
      basic-save-buffer-2()
      basic-save-buffer-1()
      basic-save-buffer()
      save-buffer()
      write-file("~/.emacs.d/ido.last" nil)
      ido-save-history()
      ido-kill-emacs-hook()
      run-hooks(kill-emacs-hook)
      kill-emacs()
      save-buffers-kill-emacs(nil)
      call-interactively(save-buffers-kill-emacs)

AFAICT there is no way to kill such an Emacs process short of kill -9
or terminating it's parent tty.  Even doing M-x ido mode RET to turn
it off didn't seem to help.