mod_groups_muc_bookmarks: fix typo/leftover from refactor The update_bookmark function no longer takes a "current" argument; passing it causes havoc in service:publish (because it gets the room JID instaed of the item as item).

This module lets you block connections to any remote servers not on a
whitelist.

``` {.lua}
s2s_whitelist = {
    "example.org",
}
```