Create only necessary resources for compute v2 and network tests

This patch leverages the set_network_resources method in order to allow
tempest api tests for compute v2 and network to create only those
network resources which are required by the test

Related-Bug: #1262334

Change-Id: I7fad33d883e66a7a0e7d079c319a4a6ba815bf45
diff --git a/tempest/api/compute/servers/test_attach_interfaces.py b/tempest/api/compute/servers/test_attach_interfaces.py
index dbb7d75..738e4a8 100644
--- a/tempest/api/compute/servers/test_attach_interfaces.py
+++ b/tempest/api/compute/servers/test_attach_interfaces.py
@@ -26,6 +26,8 @@
     def setUpClass(cls):
         if not cls.config.service_available.neutron:
             raise cls.skipException("Neutron is required")
+        # This test class requires network and subnet
+        cls.set_network_resources(network=True, subnet=True)
         super(AttachInterfacesTestJSON, cls).setUpClass()
         cls.client = cls.os.interfaces_client