bug#10478: 24.0.50; url-http-parse-headers can silently drop the response when handling BASIC AUTHENTICATION

[Eli Zaretskii]

> From: David Engster <deng@randomsample.de>
> Date: Sat, 03 Jun 2017 12:41:47 +0200
> Cc: Jerry Asher <jerry.asher@gmail.com>, 10478@debbugs.gnu.org
> 
> I'm not sure if the resulting patch will fit in the 'trivial patch'
> category.

It's hard to tell, as no diffs were posted.

Would it be possible to extract the error-handling part into a
separate function, so that the actual changes would be as short as
possible?  Then we could see if they are short enough to accept
without papers.

Thanks.