Add port cleanup for FloatingIp test cases

- there are not enough ports to run the FloatingIpSameNetwork
  tests. It is necessary to clean up the ports of deleted servers
  from previous tests.

Related-Prod: PRODX-56293
Change-Id: Ifb10f7408cf930e69722dceca53ec9d34afc24c7
diff --git a/neutron_tempest_plugin/scenario/test_floatingip.py b/neutron_tempest_plugin/scenario/test_floatingip.py
index 4225b66..ca07e28 100644
--- a/neutron_tempest_plugin/scenario/test_floatingip.py
+++ b/neutron_tempest_plugin/scenario/test_floatingip.py
@@ -85,6 +85,7 @@
         if network is None:
             network = self.network
         port = self.create_port(network, security_groups=[self.secgroup['id']])
+        self.addCleanup(self.client.delete_port, port['id'])
         if create_floating_ip:
             fip = self.create_floatingip(port=port)
         else: