iRedMail-0.8.4 installs Amavisd-new-2.6.x on CentOS 6, the SQL structure is old (compare to Amavisd-new-2.8).
Column "unchecked_lovers" is in table "amavisd.policy", this table is used while you have '@lookup_sql_dsn' enabled in Amavisd. But it's disabled by default in iRedMail, so no impact.
You can ignore it, or delete the whole Amavisd database then re-create it with the latest SQL structure here:
https://bitbucket.org/zhb/iredmail/src/ … .7.0.mysql