savehist-autosave should be wrapped in a condition-case

[Drew Adams]

Because it's always possible for a history list to end up containing
malformed entries, in my local copy of savehist.el I have added this
condition-case:

(defun savehist-autosave ()
  "Save the minibuffer history if it has been modified since the last
save."
  (condition-case nil
      (savehist-save t)
    (error nil)))

You might want to do something similar in the official version. An
alternative might be to remove the offending entry and try again to save.

Thanks,

  Drew