Don't ignore (global) userlogins/sendmail logs in per_user_logging mode

CHANGELOG

@@ -1,6 +1,8 @@
 CHANGELOG Roundcube Webmail
 ===========================
 
+- Don't ignore (global) userlogins/sendmail logs in per_user_logging mode
+
 RELEASE 1.1.10
 --------------
 - Fix file disclosure vulnerability caused by insufficient input validation [CVE-2017-16651] (#6026)

program/lib/Roundcube/rcube.php

@@ -1306,9 +1306,9 @@ class rcube
         $log_dir = null;
 
         // per-user logging is activated
-        if (self::$instance && self::$instance->config->get('per_user_logging', false) && self::$instance->get_user_id()) {
+        if (self::$instance && self::$instance->config->get('per_user_logging') && self::$instance->get_user_id()) {
             $log_dir = self::$instance->get_user_log_dir();
-            if (empty($log_dir))
+            if (empty($log_dir) && !in_array($name, array('errors', 'userlogins', 'sendmail'))) {
                 return false;
         }
         else if (!empty($log['dir'])) {