Code review comment for lp:~wallyworld/launchpad/delete-bugtask-log-activity-1324

> Why the @block_implicit_flushes ?

I copied the existing notify_bugtask_added() method which used this.

> If you plan on landing this branch separately from lp:~wallyworld/launchpad
> /delete-bugtasks-1324, I recommend creating a separate bug for it. It was a
> bit surprising that the linked bug was "Can't delete spurious "Affects" lines
> (bugtasks) from bug reports"

This branch is part 2 of the work to fix that bug. The first branch did the core work, this one adds the activity recording. I am going to land both together.