recursion error in nmbd

[Luke Kenneth Casson Leighton]

> 2) mark response records with a "being dealt with" flag and don't deal
> with them if the flag is set. 

not that i know exactly what the issues are any more, but a netbios name
should not be used (i.e no 138 or 139 traffic accepted) when:

- a name is being registerd
- a name has been marked as "in conflict"
- a name has started to be de-registered.