fix(core) Fix template file path detection

issue #5951

include/class_pluglist.inc

@@ -549,6 +549,8 @@ class pluglist {
       $plugin_dir = $plist->get_path($index);
       $plugin     = $plist->dirlist[$index];
     }
+    /* Used by get_template_path */
+    session::set('plugin_dir', $plugin_dir);
 
     try {
       if ($forceCleanup) {

plugins/generic/welcome/main.inc

@@ -2,7 +2,7 @@
 /*
   This code is part of FusionDirectory (http://www.fusiondirectory.org/)
   Copyright (C) 2003  Cajus Pollmeier
-  Copyright (C) 2011-2016  FusionDirectory
+  Copyright (C) 2011-2019  FusionDirectory
 
   This program is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
@@ -20,7 +20,6 @@
 */
 
 if (!$cleanup) {
-  session::set('plugin_dir', dirname(__FILE__));
   $smarty->assign('iconmenu', $plist->show_iconmenu());
   $smarty->assign('header', print_header('geticon.php?context=applications&icon=config-welcome&size=48', sprintf(_('Welcome %s!'), $ui->cn)));
   $smarty->assign('year', date('Y'));
@@ -28,5 +27,3 @@ if (!$cleanup) {
 
   $display = $smarty->fetch(get_template_path('welcome.tpl', TRUE));
 }
-
-?>