Currently if a new port is created by a tenant with whom
the network is shared (tenant is not the owner but has
network shared via RBAC) , the port is allocated on the default
subnet. This patch allows the tenant to create/update a port on
any subnet which is actually a part of a shared network, owned by
another tenant.
Tempest test in [1]
[1]: https://review.openstack.org/521413
Change-Id: I1046f6b13e68b1e274cc8f62f5b30aa5f8d71cdc
Closes-Bug: #1543756
8236e83dec