fixes #854 adding trigger on tag deletion

admin/include/functions.php

@@ -1655,6 +1655,8 @@ DELETE
 ;';
   pwg_query($query);
 
+  trigger_notify("delete_tags", $tag_ids);
+
   update_images_lastmodified($image_ids);
   invalidate_user_cache_nb_tags();
 }

tools/triggers_list.php

@@ -89,6 +89,12 @@ array(
   'vars' => array('array', 'ids'),
   'files' => array('admin\include\functions.inc.php (delete_elements)'),
 ),
+array(
+  'name' => 'delete_tags',
+  'type' => 'trigger_notify',
+  'vars' => array('array', 'tag_ids'),
+  'files' => array('admin\include\functions.inc.php (delete_tags)')
+),
 array(
   'name' => 'delete_user',
   'type' => 'trigger_notify',