s4:samldb LDB module - "userAccountControl" = 0 means UF_NORMAL_ACCOUNT on add

Windows Server 2008 has changed semantics in comparison to Server 2003.

Reviewed-by: Andrew Bartlett <abartlet@samba.org>
s4:samldb LDB module - permit "userAccountControl" modifications without acct. type

Obviously this defaults to UF_NORMAL_ACCOUNT. Some background can be found in
MS-SAMR section 3.1.1.8.10.

Reviewed-by: Andrew Bartlett <abartlet@samba.org>

Autobuild-User(master): Andrew Bartlett <abartlet@samba.org>
Autobuild-Date(master): Wed Jun  5 03:26:25 CEST 2013 on sn-devel-104