Do not upcase x509-username-field for mixed-case arguments.

Do not upcase x509-username-field for mixed-case arguments.

I revisited options.c to refine its brute-force upcasing behavior. Now, the
upcasing is done only if the option argument is all lowercase. Mixed-case
arguments and those with the "ext:" prefix are left unchanged. This
preserves the original intent of the "helpful" upcasing feature for
backwards compatibility while limiting its scope in a straightforward way.

Signed-off-by: Andris Kalnozols <andris@hpl.hp.com>
Signed-off-by: Steffan Karger <steffan.karger@fox-it.com>
Acked-by: Arne Schwabe <arne@rfc2549.org>
Message-Id: <53B1BDD8.8020705@karger.me>
Signed-off-by: Gert Doering <gert@greenie.muc.de>
(cherry picked from commit f4e0ad82b0eaccce965074c1ceec2b7e3853dc0d)