(Bug 1337614) Fix forum topic deletion error message.

The objectional material refactoring removed the reported field
from the interaction_forum_post table. Update the code for deleting
topics and posts to match.

Change-Id: I77c7d9e80828174532cdc03c4aeb115b2602ef66
Signed-off-by: Nigel Cunningham <nigelc@catalyst-au.net>
Merge "(Bug 1337614) Fix forum topic deletion error message."