bug#22754: 25.1.50; Rmail does not follow RFC 2822

[Eli Zaretskii]

> From: Marcin Borkowski <mbork@mbork.pl>
> Date: Sun, 21 Feb 2016 11:28:27 +0100
> 
> Rmail inserts lower-case field names in the header, which goes against
> RFC 2822 (pp. 22 and 23, see
> https://tools.ietf.org/html/rfc2822#page-22).  It seems that the problem
> affects Cc: and In-reply-to: fields.

I use Rmail all the time, and these headers are capitalized in my
reply messages.  So please provide a recipe starting from "emacs -Q",
there could be some other factor at work here.

Thanks.