r24789: Add implementation of machine-authenticated connection to netlogon

r24789: Add implementation of machine-authenticated connection to netlogon
pipe used when connecting to win2k and newer domain controllers. The
server may be configured to deny anonymous netlogon connections which
would stop domain join verification step. Still, winnt domains require
such smb sessions not to be authenticated using machine credentials.
Creds employed in smb session cannot have a username in upn form, so
provide the separate function to use machine account.

rafal