Update README.md

README.md

 ### Download
-数据/代码github地址：https://github.com/logpai/loghub.
+数据github地址：https://github.com/logpai/loghub.
 
 ## Spark
 Apache Spark (https://spark.apache.org) is a unified analytics engine for big data processing, with built-in modules for streaming, SQL, machine learning and graph processing. Spark has been widely deployed in industry for big data processing.