In ReplicationBroker, removed null checks on the replication domain.
Had to change integrated unit tests to pass a dummy replication domain.


ReplicationBroker.java:
Removed null checks on the domain.

DummyReplicationDomain.java: ADDED

ReplicationTestCase.java:
Removed the replicationDomain parameter which were always passed as null.
Could remove one openReplicationSession() method.
Passed in a DummyReplicationDomain when creating a ReplicationBroker.


ExternalChangeLogTest.java, ReplicationServerTest.java, HistoricalCsnOrderingTest.java, StateMachineTest.java:
Passed in a DummyReplicationDomain when creating a ReplicationBroker.
Also consequence of removing the replicationDomain parameter in ReplicationTestCase.openReplicationSession().