Hago limpieza en el servidor de cluster.

 On branch issue_20
 Changes to be committed:

	modified:   clusterServer/main.py
	modified:   clusterServer/reactor/clusterServerReactor.py
	modified:   database/clusterServer/clusterServerDB.py
	modified:   database/tests/clusterServerDBTests.py
	modified:   testing/dummyVMServer.py
	modified:   virtualMachineServer/main.py
	modified:   virtualMachineServer/vmServer.py
	modified:   virtualMachineServer/vmServerCallback.py