This patch takes the work the jerry did for beta2, and generalises it:

This patch takes the work the jerry did for beta2, and generalises it:

 - The 'not implmented' checks are now done by all auth modules
 - the ntdomain/trustdomain/winbind modules are more presise as to
   what domain names they can and cannot handle
 - The become_root() calls are now around the winbind pipe opening only,
   not the entire auth call
 - The unix username is kept seperate from the NT username, removing the
   need for 'clean off the domain\' in parse_net.c
 - All sid->uid translations are now validated with getpwuid() to put a very
   basic stop to logins with 'half deleted' accounts.

Andrew Bartlett
(This used to be commit 85f88191b9927cc434645ef4c1eaf5ec0e8af2ec)