As the heat format of the Instance has been changed from AWS to HOT,
the PublicIp attribute is not longer available. A "address" should
be used instead.
Also, the resource name has to be renamed from PublicIp to the
assigned-ip, as it is not necessary public
Change-Id: I9a4e99680939b6e31d47a1f181b92d1878f65a5e
Closes-Bug: #1319135