HBASE-15171 Addendum removes extra loop (Yu Li)

hbase-server/src/main/java/org/apache/hadoop/hbase/mapreduce/PutSortReducer.java

@@ -67,13 +67,12 @@ public class PutSortReducer extends
         for (List<Cell> cells: p.getFamilyCellMap().values()) {
           for (Cell cell: cells) {
             KeyValue kv = KeyValueUtil.ensureKeyValue(cell);
-            map.add(kv);
-          }
-        }
-        for(KeyValue kv: map){
+            if (map.add(kv)) {// don't count duplicated kv into size
               curSize += kv.heapSize();
             }
           }
+        }
+      }
       context.setStatus("Read " + map.size() + " entries of " + map.getClass()
           + "(" + StringUtils.humanReadableInt(curSize) + ")");
       int index = 0;