move example blacklist_helo list to docs/ with instructions to install

Jesse Norell

2016-02-08 8c8acac7bb7160e3833b9351bccb8d9c643bddf6

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ALTER TABLE  `mail_user` ADD  `autoresponder_subject` VARCHAR(255) NOT NULL DEFAULT 'Out of office reply' AFTER  `autoresponder_end_date`;