Merge branch 'master' into 'master'

Fix for #4335 and removal of unnecessary file

See merge request ispconfig/ispconfig3!706

Author: Till Brehm

install/tpl/mysql-virtual_outgoing_bcc.cf

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