Fishy looking comment_agents in the livejournal importer

[Denis-de-Bernardy]

Found this while looking into #10389.

There are things like:

// should this be an agent instead?
'comment_agent' => $lj_comment_parent,

...

// should be comment_parent instead?
while ( $comments = $wpdb->get_results( "SELECT comment_ID, comment_agent FROM {$wpdb->comments} WHERE comment_type = 'livejournal' AND comment_agent != '0' LIMIT 5000", OBJECT ) ) {

array( 'comment_parent' => $this->get_wp_comment_ID( $comment->comment_agent ), 'comment_type' => 'livejournal-done' ),

Those are intentional. They are required to maintain and manipulate the threading of comments during import, and everything is cleaned up towards the end of the importer.

This could all potentially be rewritten to use the new commentmeta table in 2.9 though if someone was interested.