default named.conf in bind ports and slaving from f-root

[Olafur Gudmundsson]

Hi Thomas, 

RFC7706  appendix B.1 is relevant here, https://tools.ietf.org/html/rfc7706#appendix-B.1
it strongly recommends relying on more than one provider just to avoid cases like this 
Strongly recommend that you add the all the other root servers (including F) to your patch along with the ICANN servers as that will allow 
Bind to try any available server for the zone transfer. 

Olafur