Code review comment for ~lgp171188/launchpad:add-locked-column-to-bug-table

I think I misread Colin's comment about this field.

> An enum is better than a boolean here, since for now we want "unlocked" and "comment-only" lock states, but it's conceivable that we might want others in future.

So I am updating the status to 'Work in progress' and no review is needed right now.