bug#14120: [Robert Weiner] Emacs history selection non-string arguments causing failures for a long time

[Robert Weiner]

> On Feb 16, 2020, at 8:52 PM, Stefan Monnier <monnier@iro.umontreal.ca> wrote:
> 
> The docstring of `load-history` says that (car load-elt) should never be
> anything else than a string or nil.  So the right fix is likely
> elsewhere.

Yes, I noticed that too, so maybe this is just a patch that allows history to 
work while filtering out these errant entries which may be as much as 20% of my 
total entries.  I hope someone can find the injection source.

Bob