Delete SocketSession which was only referenced and not used in unit-tests.

Ludovic Poitou

06.42.2013 af14c99941ac3ed7713904eff52d981c3e356381

opendj-sdk/opends/src/server/org/opends/server/replication/protocol/SocketSession.java does not exist in tree 708c908081d645f90b85dcbcd505cbcd6112052e