Fix 1406, exception when starting distribute mode

To fix issue : https://github.com/nuvolabase/orientdb/pull/1406, 
On distributed mode, exception will throw when starting server, error saving distribute configuration which should not be save. Following is distribute configuration document format: 
{"@type":"d","@version":0,"internal":{"@type":"d","@version":0,"synchronization":false},"index":{"@type":"d","@version":0,"synchronization":false},"ODistributedConflict":{"@type":"d","@version":0,"synchronization":false},"*":{"@type":"d","@version":0,"synchronization":true,"master":"$auto","synch-replicas":1,"asynch-replicas":"100%"}}