A recent change[0] to address PEP8 issues resulted in an unintended
behavior modification, in some cases resulting in MAAS allocation of
multiple IP addresses to the same NIC.
This reverts to the original code logic.
[0] 1755930331
Change-Id: I6dccd1b60c414e3aa966085e81dc0b61244e9814
a75704b8cb