HBASE-22890 Verify the file integrity in persistent IOEngine

Author: ZhaoBQ

hbase-server/src/main/java/org/apache/hadoop/hbase/io/hfile/bucket/FileIOEngine.java

@@ -371,7 +371,7 @@ public byte[] calculateChecksum()
       }
     }
     MessageDigest messageDigest = MessageDigest.getInstance(algorithmName);
-    messageDigest.update(sb.toString().getBytes());
+    messageDigest.update(Bytes.toBytes(sb.toString()));
     return messageDigest.digest();
   }