bug#15372: eshell gives environment variables high precedence

[Glenn Morris]

Please don't post to bug-gnu-emacs via the newsgroup (it bypasses the
bug tracker).

Aidan Gauland wrote:

> Glenn Morris <rgm@gnu.org> writes:
>
>> If you set eshell-prefer-lisp-variables non-nil, it works.
>
> I will add a mention of this in the manual, since users should not have
> to hunt that variable down as you did.

Actually I believe I fixed the issue. But that variable can be mentioned
anyway, just not in this context.