Replace anonymous class with ThreadLocal.withInitial

Java 8 Introduced ThreadLocal.withInitial which is a simpler alternative
to creating an anonymous inner class to initialise a ThreadLocal
instance.

Change-Id: I23a7cefc6318de35c03520893d671c05a2c3c0be
diff --git a/src/main/java/com/googlesource/gerrit/plugins/its/base/its/ItsConfig.java b/src/main/java/com/googlesource/gerrit/plugins/its/base/its/ItsConfig.java
index 8da5b5d..d7193fd 100644
--- a/src/main/java/com/googlesource/gerrit/plugins/its/base/its/ItsConfig.java
+++ b/src/main/java/com/googlesource/gerrit/plugins/its/base/its/ItsConfig.java
@@ -57,12 +57,7 @@
   private final Config gerritConfig;
 
   private static final ThreadLocal<Project.NameKey> currentProjectName =
-      new ThreadLocal<Project.NameKey>() {
-        @Override
-        protected Project.NameKey initialValue() {
-          return null;
-        }
-      };
+      ThreadLocal.withInitial(() -> null);
 
   public static void setCurrentProjectName(Project.NameKey projectName) {
     currentProjectName.set(projectName);