HDFS-17209. Correct comments to align with the code (#6110). Contributed by Yu Wang.

Reviewed-by: Inigo Goiri <inigoiri@apache.org>
Signed-off-by: Ayush Saxena <ayushsaxena@apache.org>

Author: yuw1

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/datanode/DataNode.java

@@ -2569,7 +2569,7 @@ public void shutdown() {
     if (this.threadGroup != null) {
       int sleepMs = 2;
       while (true) {
-        // When shutting down for restart, wait 2.5 seconds before forcing
+        // When shutting down for restart, wait 1 second before forcing
         // termination of receiver threads.
         if (!this.shutdownForUpgrade ||
             (this.shutdownForUpgrade && (Time.monotonicNow() - timeNotified