[arch-general] Belated Arch-Conf pacman improvement suggestion

Allan,

While the pacman part of the conference is over, I just ran into an issue that would fit the pacman improvement segment.

When updating, if on the first repo, the first mirror selected times-out, then mark that repo failed for the remaining repo checks so you don't sit through two more timeouts on a repo that is known failed at that point.

If arch.mirror.constant.com was down yesterday, I could have made the segment :)