Merge pull request #3906 from jsoref/logrecorder-off

[JENKINS-56200] LogRecorder: support turning off a log recorder

core/src/main/java/hudson/logging/LogRecorder.java

@@ -466,5 +466,5 @@ public class LogRecorder extends AbstractModelObject implements Saveable {
      * Log levels that can be configured for {@link Target}.
      */
     public static List<Level> LEVELS =
-            Arrays.asList(Level.ALL, Level.FINEST, Level.FINER, Level.FINE, Level.CONFIG, Level.INFO, Level.WARNING, Level.SEVERE);
+            Arrays.asList(Level.ALL, Level.FINEST, Level.FINER, Level.FINE, Level.CONFIG, Level.INFO, Level.WARNING, Level.SEVERE, Level.OFF);
 }