HDFS-14917. Change the ICON of "Decommissioned & dead" datanode on "dfshealth.html". Contributed by Xieming Li

hadoop-hdfs-project/hadoop-hdfs/src/main/webapps/static/hadoop.css

@@ -262,7 +262,7 @@ header.bs-docs-nav, header.bs-docs-nav .navbar-brand {
 
 .dfshealth-node-down-decommissioned:before {
     color: #c7254e;
-    content: "\e017";
+    content: "\e090";
 }
 
 .dfshealth-node-down-maintenance:before {