JAVA-1071: authenticate no longer fails if there is no primary

Author: jyemin

src/main/com/mongodb/DBTCPConnector.java

@@ -628,7 +628,7 @@ public boolean isOpen(){
 
     @Override
     public CommandResult authenticate(MongoCredential credentials) {
-        checkMaster(false, true);
+        checkMaster(false, false);
         final DBPort port = _myPort.get(false, ReadPreference.primaryPreferred(), null);
 
         try {