Replace the use of 'os_adm' with 'os_admin'

Property 'os_adm' has been moved to 'os_admin' in version Pike, and
it will be removed in version Queens. This patch is to replace the
usage of 'os_adm' with 'os_admin' in Tempest tests.

Change-Id: Ie4cf457d0a521910a82e41e7dad775df75d56587
diff --git a/tempest/api/compute/admin/test_delete_server.py b/tempest/api/compute/admin/test_delete_server.py
index 2569161..83444b9 100644
--- a/tempest/api/compute/admin/test_delete_server.py
+++ b/tempest/api/compute/admin/test_delete_server.py
@@ -29,7 +29,7 @@
     def setup_clients(cls):
         super(DeleteServersAdminTestJSON, cls).setup_clients()
         cls.non_admin_client = cls.servers_client
-        cls.admin_client = cls.os_adm.servers_client
+        cls.admin_client = cls.os_admin.servers_client
 
     @decorators.idempotent_id('99774678-e072-49d1-9d2a-49a59bc56063')
     def test_delete_server_while_in_error_state(self):
diff --git a/tempest/api/compute/admin/test_servers.py b/tempest/api/compute/admin/test_servers.py
index a492b43..789049b 100644
--- a/tempest/api/compute/admin/test_servers.py
+++ b/tempest/api/compute/admin/test_servers.py
@@ -133,7 +133,7 @@
         # self.create_test_server() here as this method creates the server
         # in the "primary" (i.e non-admin) tenant.
         test_server, _ = compute.create_test_server(
-            self.os_adm, wait_until="ACTIVE", name=name, **network_kwargs)
+            self.os_admin, wait_until="ACTIVE", name=name, **network_kwargs)
         self.addCleanup(self.client.delete_server, test_server['id'])
         server = self.client.show_server(test_server['id'])['server']
         self.assertEqual(server['status'], 'ACTIVE')
diff --git a/tempest/api/volume/admin/test_volume_quota_classes.py b/tempest/api/volume/admin/test_volume_quota_classes.py
index 016d87a..b8a61fd 100644
--- a/tempest/api/volume/admin/test_volume_quota_classes.py
+++ b/tempest/api/volume/admin/test_volume_quota_classes.py
@@ -73,7 +73,7 @@
 
         # Verify current project's default quotas
         default_quotas = self.admin_quotas_client.show_default_quota_set(
-            self.os_adm.credentials.tenant_id)['quota_set']
+            self.os_admin.credentials.tenant_id)['quota_set']
         self.assertThat(default_quotas.items(),
                         matchers.ContainsAll(body.items()))