On ipam_release_address, kuryr unset all the neutron ports with
the released IP address. This is incorrect because IP address
is not unique across an OpenStack deployment.
This patch adds a check for verifying the subnet of a port
before reseting the port. If the port's subnet doesn't
match the subnet of the pool, the port is not the target and
won't be reset.
In order to identify the subnet given a pool ID. This patch
tags each kuryr created subnet with the pool ID.
Change-Id: I8f85ae53c924aa1f4ff877f52a56d267f984dbf5
Closes-Bug: #1782947
Related-Bug: #1782942