HDFS-15951. Remove unused parameters in NameNodeProxiesClient (#2859)

Signed-off-by: Takanobu Asanuma <tasanuma@apache.org>
(cherry picked from commit 9e2d5d6d05a2d8b657d06fdf3db49d588394a579)

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

@@ -78,11 +78,6 @@ public class NameNodeProxiesClient {
   private static final Logger LOG = LoggerFactory.getLogger(
       NameNodeProxiesClient.class);
 
-  /** Maximum # of retries for HAProxy with HAServiceProtocol. */
-  private static final int MAX_RETRIES = 3;
-  /** Initial retry delay for HAProxy with HAServiceProtocol. */
-  private static final int DELAY_MILLISECONDS = 200;
-
   /**
    * Wrapper for a client proxy as well as its associated service ID.
    * This is simply used as a tuple-like return type for created NN proxy.