NSHost bug/annoyance

[Larry Campbell]

If you call [NSHost hostWithAddress] with a host that lacks a reverse 
name mapping you get this spew:

Nov 12 14:32:10 snmptest[10286] Host '209.104.33.44' not found using 
'gethostbyaddr()' - perhaps the address is wrong or networking is not 
set up on your machine

This is really annoying. Most of the time this is not the user's fault 
and there's nothing they can do about it. I think returning nil in this 
case is quite sufficient.

- lc