bug#18704: nss-mdns home-page and source URL no longer valid

[Mark H Weaver]

Like libdaemon <http://bugs.gnu.org/18639>, the home-page and source URL
for nss-mdns has vanished, so all the builds on hydra are failing.

I found the following alternate URLs to download the source.

http://ftp.de.debian.org/debian/pool/main/n/nss-mdns/nss-mdns_0.10.orig.tar.gz
http://pkgs.fedoraproject.org/repo/pkgs/nss-mdns/nss-mdns-0.10.tar.gz/03938f17646efbb50aa70ba5f99f51d7/nss-mdns-0.10.tar.gz

I'll shortly push a fix analogous to the one for bug #18639.

      Mark