HDFS-14416. Fix TestHdfsConfigFields for field dfs.client.failover.resolver.useFQDN. Contributed by Fengnan Li.

hadoop-hdfs-project/hadoop-hdfs-client/src/main/java/org/apache/hadoop/hdfs/client/HdfsClientConfigKeys.java

@@ -291,7 +291,7 @@ public interface HdfsClientConfigKeys {
     String  RESOLVE_ADDRESS_NEEDED_KEY = PREFIX + "resolve-needed";
     boolean RESOLVE_ADDRESS_NEEDED_DEFAULT = false;
     String RESOLVE_SERVICE_KEY = PREFIX + "resolver.impl";
-    String  RESOLVE_ADDRESS_TO_FQDN = PREFIX + "useFQDN";
+    String  RESOLVE_ADDRESS_TO_FQDN = PREFIX + "resolver.useFQDN";
     boolean RESOLVE_ADDRESS_TO_FQDN_DEFAULT = true;
   }