rspamd: Lower spam threshold on misaligned Reply-To/To fields

When people send patches to pacman-dev, either with the wrong list address or a perceived wrong email header it would most likely be default marked as spam and stuffed into Junk for people using our email server.

This attempts at lowering the score to something we can live with until a gitlab migration.

This patch is not tested.

Signed-off-by: Morten Linderud morten@linderud.pw