Remove unused "service" argument from tempest client manager

It was removed by tempest breaking our CI.

Change-Id: I8a3311a2d3a9c16f316e1621a270c2a5f9916201
Depends-On: I5cefad7d9d8f6db51fd891ecce9879979c83baee
diff --git a/ironic_tempest_plugin/services/introspection_client.py b/ironic_tempest_plugin/services/introspection_client.py
index 5bb03c2..3b1a75b 100644
--- a/ironic_tempest_plugin/services/introspection_client.py
+++ b/ironic_tempest_plugin/services/introspection_client.py
@@ -23,9 +23,8 @@
 class Manager(clients.Manager):
     def __init__(self,
                  credentials=ADMIN_CREDS,
-                 service=None,
                  api_microversions=None):
-        super(Manager, self).__init__(credentials, service)
+        super(Manager, self).__init__(credentials)
         self.introspection_client = BaremetalIntrospectionClient(
             self.auth_provider,
             CONF.baremetal_introspection.catalog_type,