Refactor TestCreateNetwork: Setup cmd in setUp() in TestCreateNetworkIdentityV3
Refactor TestCreateNetwork: Setup cmd in setUp() in TestCreateNetworkIdentityV3

This patch setup the tested command only once in setUp() for TestCreateNetworkIdentityV3.

Change-Id: Iff5119fa24c9cc0caa72ff0e8f63e8dcac72470a
Implements: blueprint osc-network-unit-test-refactor
Related-to: blueprint neutron-client

openstack/python-openstackclient,redhat-openstack/python-openstackclient,redhat-openstack/python-openstackclient,openstack/python-openstackclient,dtroyer/python-openstackclient,dtroyer/python-openstackclient