HDFS-12987. Document - Disabling the Lazy persist file scrubber.. Contributed by Karthik Palanisamy.

hadoop-hdfs-project/hadoop-hdfs/src/main/resources/hdfs-default.xml

@@ -475,8 +475,8 @@
   <description>
     The NameNode periodically scans the namespace for LazyPersist files with
     missing blocks and unlinks them from the namespace. This configuration key
-    controls the interval between successive scans. Set it to a negative value
-    to disable this behavior.
+    controls the interval between successive scans. If this value is set to 0,
+    the file scrubber is disabled.
   </description>
 </property>
 <property>