Fix messages list sorting with THREAD=REFS

Aleksander Machniak

2013-06-29 d2fa254d904ac16b8faba723af4f477923324e86

 program/lib/Roundcube/rcube_imap.php

@@ -1336,7 +1336,7 @@
        // THREAD=REFERENCES:     sorting by sent date of root message
        // THREAD=REFS:           sorting by the most recent date in each thread

        if ($this->get_capability('THREAD') != 'REFS') {
        if ($this->threading != 'REFS') {
            $sortby = $this->sort_field ? $this->sort_field : 'date';
            $index  = $this->index_direct($this->folder, $sortby, $this->sort_order, false);