Test cases for Endpoints V3 API

Adds a test script "test_endpoints.py" so as to test CREATE, DELETE,
LIST, UPDATE API actions. endpoints_client.py is added with all the required
methods. Implementation done in JSON and XML interfaces.

Implements: blueprint keystone-v3-endpoints-api-test

Change-Id: Icd47728d161d440440f6b4f103a55125da8bbf29
diff --git a/tempest/tests/identity/base.py b/tempest/tests/identity/base.py
index 168b2ff..64b8993 100644
--- a/tempest/tests/identity/base.py
+++ b/tempest/tests/identity/base.py
@@ -28,6 +28,7 @@
         os = clients.AdminManager(interface=cls._interface)
         cls.client = os.identity_client
         cls.token_client = os.token_client
+        cls.endpoints_client = os.endpoints_client
 
         if not cls.client.has_admin_extensions():
             raise cls.skipException("Admin extensions disabled")