Module: Simplify BufferedReader creation

There is no need to pass UTF-8 charset, because it is already the
default. Moreover it is inconsistent usage of Files.newBufferedWriter()
method, because in the same class this method already used without
passing in extra charset parameter.

Change-Id: Ia8f6efa52b885b3adaeee9530dcb1db13a16fe02
diff --git a/src/main/java/com/googlesource/gerrit/plugins/multisite/Module.java b/src/main/java/com/googlesource/gerrit/plugins/multisite/Module.java
index 2c9e11e..19193af 100644
--- a/src/main/java/com/googlesource/gerrit/plugins/multisite/Module.java
+++ b/src/main/java/com/googlesource/gerrit/plugins/multisite/Module.java
@@ -14,8 +14,6 @@
 
 package com.googlesource.gerrit.plugins.multisite;
 
-import static java.nio.charset.StandardCharsets.UTF_8;
-
 import com.google.common.annotations.VisibleForTesting;
 import com.google.gerrit.lifecycle.LifecycleModule;
 import com.google.gerrit.server.config.SitePaths;
@@ -149,7 +147,7 @@
 
   private UUID tryToLoadSavedInstanceId(String serverIdFile) {
     if (Files.exists(Paths.get(serverIdFile))) {
-      try (BufferedReader br = Files.newBufferedReader(Paths.get(serverIdFile), UTF_8)) {
+      try (BufferedReader br = Files.newBufferedReader(Paths.get(serverIdFile))) {
         return UUID.fromString(br.readLine());
       } catch (IOException e) {
         log.warn(