Remove unused project_ids in test_list_projects

This is to remove unused project_ids in test_list_projects,
also to change some unnecessary instance variables to local
variables, and also to use cls.__name__ in rand_name.

Change-Id: I4ef0b16db0869597e09e62d1694dbbb13013271b
diff --git a/tempest/api/identity/admin/v3/test_list_projects.py b/tempest/api/identity/admin/v3/test_list_projects.py
index 9022b2d..cb8ea11 100644
--- a/tempest/api/identity/admin/v3/test_list_projects.py
+++ b/tempest/api/identity/admin/v3/test_list_projects.py
@@ -44,29 +44,24 @@
     @classmethod
     def resource_setup(cls):
         super(ListProjectsTestJSON, cls).resource_setup()
-        cls.project_ids = list()
-        cls.domain_id = cls.os_admin.credentials.domain_id
+        domain_id = cls.os_admin.credentials.domain_id
         # Create project with domain
-        cls.p1_name = data_utils.rand_name('project')
+        p1_name = data_utils.rand_name(cls.__name__)
         cls.p1 = cls.projects_client.create_project(
-            cls.p1_name, enabled=False,
-            domain_id=cls.domain_id)['project']
+            p1_name, enabled=False, domain_id=domain_id)['project']
         cls.addClassResourceCleanup(cls.projects_client.delete_project,
                                     cls.p1['id'])
-        cls.project_ids.append(cls.p1['id'])
         # Create default project
-        p2_name = data_utils.rand_name('project')
+        p2_name = data_utils.rand_name(cls.__name__)
         cls.p2 = cls.projects_client.create_project(p2_name)['project']
         cls.addClassResourceCleanup(cls.projects_client.delete_project,
                                     cls.p2['id'])
-        cls.project_ids.append(cls.p2['id'])
         # Create a new project (p3) using p2 as parent project
-        p3_name = data_utils.rand_name('project')
+        p3_name = data_utils.rand_name(cls.__name__)
         cls.p3 = cls.projects_client.create_project(
             p3_name, parent_id=cls.p2['id'])['project']
         cls.addClassResourceCleanup(cls.projects_client.delete_project,
                                     cls.p3['id'])
-        cls.project_ids.append(cls.p3['id'])
 
     @decorators.idempotent_id('0fe7a334-675a-4509-b00e-1c4b95d5dae8')
     def test_list_projects_with_enabled(self):
@@ -98,7 +93,7 @@
         cls.p1 = cls.projects_client.show_project(
             cls.os_primary.credentials.project_id)['project']
         # Create a test project
-        p2_name = data_utils.rand_name('project')
+        p2_name = data_utils.rand_name(cls.__name__)
         p2_domain_id = CONF.identity.default_domain_id
         cls.p2 = cls.projects_client.create_project(
             p2_name, domain_id=p2_domain_id)['project']