typo fixed from previous commit

git-svn-id: http://piwigo.org/svn/trunk@5737 68402e56-0260-453c-a942-63ccdbb3a9ee

admin/themes/default/template/photos_add_direct.tpl

@@ -18,7 +18,7 @@ jQuery(document).ready(function(){
     }
 
     var nbFiles = 0;
-    if ($("uploadBoxes").size() == 1) {
+    if ($("#uploadBoxes").size() == 1) {
       $("input[name^=image_upload]").each(function() {
         if ($(this).val() != "") {
           nbFiles++;