Fixed: #4150 Outgoing bcc warning: empty lookup result

Author: Till Brehm

install/tpl/mysql-virtual_outgoing_bcc.cf.master

@@ -4,5 +4,5 @@ dbname = {mysql_server_database}
 table = mail_user
 select_field = sender_cc
 where_field = email
-additional_conditions = and postfix = 'y' and disabledeliver = 'n' and disablesmtp = 'n'
+additional_conditions = and postfix = 'y' and disabledeliver = 'n' and disablesmtp = 'n' and sender_cc != ''
 hosts = 127.0.0.1