s4: fsmo role transfer

[Nadezhda Ivanova]

Hi guys,
Here:
http://gitweb.samba.org/?p=nivanova/samba.git;a=shortlog;h=refs/heads/fsmo-fixed
is the work I started some time ago on transferring FSMO roles via ldap, and
Anatoliy helped me debug recently. Role transfer is essentially a normal
replication cycle on the partition when the role owner attribute is stored,
except the attribute is modified by the current owner with the name of the
new owner before replicating in. See MS-DRSR 4.1.10.5.12
ProcessFsmoRoleRequest for details.
This is only been tested for schema master transfer so far, automatic tests
are TODO, but we would appreciate a review!

Regards,
Nadya