moving SAM_ACCOUNT to include a bit field for initialized

moving SAM_ACCOUNT to include a bit field for initialized
members (such as uid and gid).  This way we will be able to
keep ourselves from writing out default smb.conf settings when
the admin doesn't want to,  That part is not done yet.

Tested compiles with ldap/tdb/smbpasswd.  Tested connection with smbpasswd
backend.

oh...and smbpasswd doesn'y automatically expire accounts after 21 days
from the last password change either now.  Just ifdef'd out that code
in build_sam_account().

Will merge updates into 2.2 as they are necessary.

jerry