Comment 14 for bug 607960

Rearranging the status component gives us:

  (BugTask.status in (10, 20,21,22,25)) OR

 ((BugTask.status = 15) AND (
    (Bug.date_last_message IS NOT NULL AND
     BugTask.date_incomplete <= Bug.date_last_message))
 OR
 (
    (Bug.date_last_message IS NULL OR BugTask.date_incomplete > Bug.date_last_message)))

which is a little easier to read though no different to the planner.

15 is incomplete, so the middle bit is:
incomplete messages with a last message(date_last_message is not null) where the message is newer than the incompleteness
OR
there is no last message
OR
but the bug was made incomplete after the last message.

This all cancels out: we should just not restrict it.