netlogon failure detection on samba-3.0.25a

[boyang]

problem: samba as domain member, and there are several NT4-style DCs, if
netlogon service on PDC is disabled, domain users cannot login.

proposed solution:
1. add get_all_rpc_dc_name in source/libsmb/namequery_dc.c to get all
NT4-style DCs whose node status response is NT_STAUS_OK. waste node
status query RTTs. in source/auth/auth_domain.c:check_ntdomain_security,
walk on the DCs' list and try to logon, if return is
NT_STATUS_NETLOGON_NOT_STARTED, try next until failure or success.
2. before call rpc_dc_name, pass the dcname & dcip
that client try to logon, but failed with
NT_STATUS_NETLOGON_NOT_STARTED, and rpc_dc_name
search the domain DCs' list from position after that dcname, and returns
one DC whose node status response is ok.

doest it make sense?