[sfc] Remove setup_clients method

As tempest.scenario.manager was announced stable interface in Tempest
27.0.0[1] it can be now reused in plugins.

Removed methods:
    * setup_clients

Etherpad concerning this effort:
https://etherpad.opendev.org/p/tempest-scenario-manager-cleanup

[1] https://docs.openstack.org/releasenotes/tempest/v27.0.0.html#release-notes-27-0-0

Change-Id: If6af3155645be06351cb78506d3ad2dfaac4d059
diff --git a/neutron_tempest_plugin/sfc/tests/scenario/manager.py b/neutron_tempest_plugin/sfc/tests/scenario/manager.py
index b4c9fe3..394fb02 100644
--- a/neutron_tempest_plugin/sfc/tests/scenario/manager.py
+++ b/neutron_tempest_plugin/sfc/tests/scenario/manager.py
@@ -32,22 +32,6 @@
 
     credentials = ['primary']
 
-    @classmethod
-    def setup_clients(cls):
-        super(ScenarioTest, cls).setup_clients()
-        # Clients (in alphabetical order)
-        cls.keypairs_client = cls.os_primary.keypairs_client
-        cls.servers_client = cls.os_primary.servers_client
-        # Neutron network client
-        cls.networks_client = cls.os_primary.networks_client
-        cls.ports_client = cls.os_primary.ports_client
-        cls.routers_client = cls.os_primary.routers_client
-        cls.subnets_client = cls.os_primary.subnets_client
-        cls.floating_ips_client = cls.os_primary.floating_ips_client
-        cls.security_groups_client = cls.os_primary.security_groups_client
-        cls.security_group_rules_client = (
-            cls.os_primary.security_group_rules_client)
-
     # ## Test functions library
     #
     # The create_[resource] functions only return body and discard the