RM7213 Added IPPolicyCIDR.{first_ip, last_ip}

* Tested against production dbs.
* There was a bug in master when comparing it to the changes I had made, thus 2 commits instead of one (I had got the boolean sign wrong for allocated IPs). 

I am confused. There is no table created in the `upgrade()`. The only SQL in the `upgrade()` is a `SELECT` followed by many `UPDATE`s. We could reverse the `upgrade()` by `UPDATE`-ing all the columns back to `null` if you wish.