mod_bookmarks2: Fix handling of nick and password elements This form of child retrieval fails when the stanza elements internally don't have an 'xmlns' attribute, which can happen sometimes for some reason, including when they have been constructed via the stanza builder API. When that is the case then the explicit namespace arguemnt does not match the nil value of the internal attribute. Calling `:get_child()` without the namespace argument does the right thing here, with both nil and the parent namespace as valid values for the internal attribute.

# Introduction

This module adds a room configuration option to hide inline media from MUCs and
display them as links instead.

This can be useful in public channels where content posted by users should not
be shown by default.

# Configuring

## Enabling

``` {.lua}
Component "rooms.example.net" "muc"
modules_enabled = {
    "muc_hide_media";
}
```

## Settings

A default setting can be provided in the config file:

``` {.lua}
muc_room_default_hide_media = true
```