An update sent by a replicated LDAP server is tagged with a ChangeNumber generated by a ChangeNumberGenerator. One component of the ChangeNumber is a timestamp,
Because we want the timestamp of the ChangeNumbers to be consistently growing across the whole topology and not only inside each server independently, the ChangeNumberGenerator must be adjusted with the timestamp of the updates 
received from the other servers of the topology. The code was already here but erroneously used.

Unit test written accordingly. It also required some changes in ProtocolWindowTest unit test to isolate it from the other unit tests.