[MaraDNS list] Patch for easydns tarpit issue

[Sam Trenholme]

Here is a patch that makes Deadwood greatly favor using a glued NS
referral for the first NS record when chasing a query.  This should
minimize the chance of falling in to something like an easydns tarpit
without all of the complexity and overhead of keeping track of which
DNS server we've been at already.

If the patch gets scrubbed, it is also here:

http://maradns.org/deadwood/patches/deadwood-3.0.05-easydns-tarpit.patch

- Sam