Only moderators should be able to send mail to alias

==== Required information ====
- iRedMail version (check /etc/iredmail-release):  0.9.2
- Linux/BSD distribution name and version: Debian
- Store mail accounts in which backend (LDAP/MySQL/PGSQL): mysql
- Web server (Apache or Nginx): apache
- Manage mail accounts with iRedAdmin-Pro? yes
- Related log if you're reporting an issue:
====

Only moderators should be able to send email to the alias, but it delivers email from anybody.