change to config file missing from rev1580

[JohnDoh]

i think this change is missing an update to config/main.inc.php.dist (or atleast some instructions).

  // these cols are shown in the message list
  // available cols are: subject, from, to, cc, replyto, date, size, encoding
- $rcmail_config['list_cols'] = array('subject', 'from', 'date', 'size');
+ $rcmail_config['list_cols'] = array('flag', 'subject', 'from', 'date', 'size');

without this the flag/unflag option is available in the interface but there is no flag column in the message table which doesnt make much sense.

sorry for opening a new ticket but it wouldnt let me reopen the original (#1484623)

[alec]

Fixed in r1584.