private void resetCtlFile() {
        // System.err.println("reset limit to: "+defaultLevelCtrl.getLevelLimit());
        Logger.getLogger("").setLevel(defaultLevelCtrl.getLevelLimit());
        try {
            if (ctlFile != null) {
                ctlFile.close();
            }
        } catch (java.io.IOException ign) {}
        ctlFile = null;
        try {
            if (ctlFileAppender != null) {
                ctlFileAppender.close();
            }
        } catch (java.io.IOException ign) {}
        ctlFileAppender = null;
        mapBuf = null;
        levelControllerRepo = null;
    }
level controller for default levels (first-time logging
or logging without a logcontrol file)
vespalog/src/main/java/com/yahoo/log/VespaLevelControllerRepo.java