Remove the port list that is not used

Ports list is already defined in BaseNetworkTest and it is used
in the floating ip test. The list self.port defined in this file
has never been used. Remove this dummy self.port definition.

Change-Id: Ic8bb47dc8c76ad7c2c4c635e40f512fe2a6fd58d
diff --git a/tempest/api/network/test_floating_ips.py b/tempest/api/network/test_floating_ips.py
index ce9c4be..2156e64 100644
--- a/tempest/api/network/test_floating_ips.py
+++ b/tempest/api/network/test_floating_ips.py
@@ -59,7 +59,6 @@
         cls.router = cls.create_router(data_utils.rand_name('router-'),
                                        external_network_id=cls.ext_net_id)
         cls.create_router_interface(cls.router['id'], cls.subnet['id'])
-        cls.port = list()
         # Create two ports one each for Creation and Updating of floatingIP
         for i in range(2):
             cls.create_port(cls.network)