Emails are repeatedly sent

Once emails have been queued, they are repeatedly sent every time cron is run. This is due to an error in the SQL that selects mail to send. Within mailq_cron()

$rs = db_query_range('SELECT * FROM {mailq_active_queue} WHERE (queue_status != %d OR queue_status != %d)
                       ORDER BY queue_priority DESC', MAILQ_STATUS_SENT, MAILQ_STATUS_FAILED, 0, variable_get('mailq_batch_size', 10));

the OR in the where clause should be changed to AND.

$rs = db_query_range('SELECT * FROM {mailq_active_queue} WHERE (queue_status != %d AND queue_status != %d)
                       ORDER BY queue_priority DESC', MAILQ_STATUS_SENT, MAILQ_STATUS_FAILED, 0, variable_get('mailq_batch_size', 10));