Merge pull request #3640 from oleg-nenashev/build/jdk11-underscore-vars

JDK-11 support: refactor code to avoid underscore variable names

core/src/main/java/hudson/PluginManager.java

@@ -1493,7 +1493,7 @@ public abstract class PluginManager extends AbstractModelObject implements OnMas
                     }
                     updateCenter.persistInstallStatus();
                     if(!failures) {
-                        try (ACLContext _ = ACL.as(currentAuth)) {
+                        try (ACLContext acl = ACL.as(currentAuth)) {
                             InstallUtil.proceedToNextStateFrom(InstallState.INITIAL_PLUGINS_INSTALLING);
                         }
                     }