Delete cache data when category is deleted.

merge -c2882 from trunk to branch 2.0
The exact copy of commit log in 2882.

git-svn-id: http://piwigo.org/svn/branches/2.0@2883 68402e56-0260-453c-a942-63ccdbb3a9ee

admin/include/functions.php

@@ -114,11 +114,16 @@ DELETE FROM '.CATEGORIES_TABLE.'
 ;';
   pwg_query($query);
 
-   $query='
+  $query='
 DELETE FROM '.OLD_PERMALINKS_TABLE.'
   WHERE cat_id IN ('.implode(',',$ids).')';
   pwg_query($query);
 
+  $query='
+DELETE FROM '.USER_CACHE_CATEGORIES_TABLE.'
+  WHERE cat_id IN ('.implode(',',$ids).')';
+  pwg_query($query);
+
   trigger_action('delete_categories', $ids);
 }