[V3 identity] Renaming service_client into services_client

1. The service_client.py file was renamed into services_client.py
2. The ServiceClient class was renamed into ServicesClient
3. The service_client variables were renamed into services_client

Partially implements blueprint consistent-service-method-names

Change-Id: I766841b19ea33426371f53651d55bc31feb6790c
diff --git a/tempest/api/identity/admin/v3/test_endpoints.py b/tempest/api/identity/admin/v3/test_endpoints.py
index 429e2e3..2ac832e 100644
--- a/tempest/api/identity/admin/v3/test_endpoints.py
+++ b/tempest/api/identity/admin/v3/test_endpoints.py
@@ -34,8 +34,8 @@
         s_type = data_utils.rand_name('type')
         s_description = data_utils.rand_name('description')
         cls.service_data = (
-            cls.service_client.create_service(name=s_name, type=s_type,
-                                              description=s_description))
+            cls.services_client.create_service(name=s_name, type=s_type,
+                                               description=s_description))
         cls.service_data = cls.service_data['service']
         cls.service_id = cls.service_data['id']
         cls.service_ids.append(cls.service_id)
@@ -56,7 +56,7 @@
         for e in cls.setup_endpoints:
             cls.client.delete_endpoint(e['id'])
         for s in cls.service_ids:
-            cls.service_client.delete_service(s)
+            cls.services_client.delete_service(s)
         super(EndPointsTestJSON, cls).resource_cleanup()
 
     @test.idempotent_id('c19ecf90-240e-4e23-9966-21cee3f6a618')
@@ -113,8 +113,8 @@
         s_type = data_utils.rand_name('type')
         s_description = data_utils.rand_name('description')
         service2 = (
-            self.service_client.create_service(name=s_name, type=s_type,
-                                               description=s_description))
+            self.services_client.create_service(name=s_name, type=s_type,
+                                                description=s_description))
         service2 = service2['service']
         self.service_ids.append(service2['id'])
         # Updating endpoint with new values