[ISSUE #242] Remove useless variable (#243)

Author: mxsm

proxy/src/main/java/io/openmessaging/storage/dledger/proxy/ConfigManager.java

@@ -30,8 +30,6 @@
 
 public class ConfigManager {
 
-    private static final Logger LOGGER = LoggerFactory.getLogger(ConfigManager.class);
-
     //groupId#selfId -> DLedgerConfig
     private final ConcurrentHashMap<String, DLedgerConfig> configMap;