Slow networking in Ubuntu Feisty caused by avahi-daemon

Or, more accurately, by the new configuration of /etc/nsswitch.conf, as detailed in this bug report:

https://bugs.launchpad.net/ubuntu/+source/avahi/+bug/94940

I got pretty frustrated hunting that down. I hope it gets fixed soon after the release of Feisty, because it’s supremely annoying to have a slow internet connection when you know that, well, it isn’t.