Finally, a fix for delete_move_next with thread sort. I _think_ this should do the...

Finally, a fix for delete_move_next with thread sort. I _think_ this should do the trick.

$thread_sort_messages was being checked, but it was always unset since it is declared in mailbox_display.php.  Once you're in the message view, that's gone.  So grab the value of thread_sort_messages from prefs, defaulting to 0 (no) if there's no pref set.

PLEASE TEST THIS - It "works for me", but that's always the case, isn't it?

git-svn-id: https://svn.code.sf.net/p/squirrelmail/code/trunk/squirrelmail@5622 7612ce4b-ef26-0410-bec9-ea0150e637f0