Ldap domain attr message quota MTA option

Direct LDAP attribute name MTA options:  (LDAP attribute name(s))
RESTRICTED. Not yet fully implemented.

See the user level LDAP attribute named by the  MTA option. Also see the Message Store option.

See also:
 * ldap_message_quota MTA Option
 * defaultmessagequota Store Option
 * Direct LDAP attribute name MTA options