[coreboot] Mailing list issues, update

[Patrick Georgi]

Hi everybody,

There have been some issues with the mailing lists hosted at coreboot.org
(spanning multiple projects: coreboot, flashrom, seabios and openbios)
related to configuration changes in response to our precious little
spammer. As a result some people have seen mailing list delivery to them
disabled due to bounces. I reversed that change for the affected users so
everybody's back in.

To avoid this type of issue going forward, the server manual has been
revised to point out some pitfalls in the mail server configuration and how
to avoid them.

Again thank you for your patience,
Patrick