Use the clear buffer on fail option. Not using it is deprecated since HBase 0.96

hbase/src/main/java/com/yahoo/ycsb/db/HBaseClient.java

@@ -117,7 +117,7 @@ public class HBaseClient extends com.yahoo.ycsb.DB
         synchronized (tableLock) {
             _hTable = new HTable(config, table);
             //2 suggestions from http://ryantwopointoh.blogspot.com/2009/01/performance-of-hbase-importing.html
-            _hTable.setAutoFlush(false);
+            _hTable.setAutoFlush(false, true);
             _hTable.setWriteBufferSize(1024*1024*12);
             //return hTable;
         }