AMBARI-20354: Files View: In non-HA environment, Files view executes with error when List of NameNodes property is cleared (sangeetar)

contrib/views/utils/src/main/java/org/apache/ambari/view/utils/hdfs/ConfigurationBuilder.java

@@ -266,7 +266,8 @@ public class ConfigurationBuilder {
     String nameservice = uri.getHost();
     String namenodeIDs = getProperty(HDFS_SITE, String.format(HA_NAMENODES_CLUSTER_PROPERTY, nameservice),
       HA_NAMENODES_INSTANCE_PROPERTY);
-    return namenodeIDs != null;
+    LOG.debug("namenodeIDs " + namenodeIDs);
+    return !StringUtils.isEmpty(namenodeIDs);
   }
 
   private static boolean hasPort(String url) throws URISyntaxException {