Refactored the code that adds Domain Admins to BUILTIN\Administrators to use the...

Refactored the code that adds Domain Admins to BUILTIN\Administrators to use the new helper functions.

- Modified create_builtin_administrators and add_builtin_administrators to take
in the domain sid to reduce the number of times it needs to be looked up.
- Changed create_builtin_administrators to call the new helper functions.
- Changed create_local_nt_token to call the new version of
create_builtin_administrators and handle the new error that can be returned.
- Made it more explicit that add_builtin_administrators is only called when
winbindd can't be pinged.
(This used to be commit f6411ccb4a1530034e481e1c63b6114a93317b29)