Now that admin_endpoint, public_endpoint, and internal_endpoint
in the common library are working, these are the changes to use
them in the openstack-network recipes.
Note that some calls to 'endpoint' that can't have separate
admin, internal, public endpoints. (E.g. network-api-bind,
network-linuxbridge, network-openvswitch, etc.) Those
will continue to use the general endpoint routine.
Partial-Bug: 1412919
Change-Id: Ia08983f6f8da8a96da22969cdb660b44f82780d6
2918234a39