mdnsresponder: remove package

mdnsresponder: remove package

The source target was broken until very recently, and it doesn't build
as it tries to use the host compiler for the client stuff, so there
cannot be many users of it.

People should use avahi instead nowadays, so so just remove it instead
of hacking it to work.

Signed-off-by: Peter Korsgaard <jacmet@sunsite.dk>