Comment 4 for bug 1782421

From what I understand the implementation of revision numbers, part of the reason we bump network's revision number, when ports/subnets are modified (even though network itself is not directly modified) is to prevent race conditions.

We had a bug reported when 2 concurrent threads trying to create overlapping subnets in one network, we couldn't prevent it in db layer. But with revision number implemented, such concurrency can be detected and prevented. Thus, my concern is that the change mentioned in your last comment may let us lose that.