Remove the wapper method show_quota_usage()

show_quota_usage() is just a wrapper method of show_quota_show(),
so it is not necessary to implement it as a library.
This patch removes it and makes tests switch to use show_quota_show()
directly.

Change-Id: Ieaa7650a9e975b5dc15575fd68235d83229e5d6c
diff --git a/tempest/api/volume/admin/test_volume_quotas.py b/tempest/api/volume/admin/test_volume_quotas.py
index ba17d9c..fe105e8 100644
--- a/tempest/api/volume/admin/test_volume_quotas.py
+++ b/tempest/api/volume/admin/test_volume_quotas.py
@@ -73,8 +73,9 @@
 
     @test.idempotent_id('18c51ae9-cb03-48fc-b234-14a19374dbed')
     def test_show_quota_usage(self):
-        quota_usage = self.admin_quotas_client.show_quota_usage(
-            self.os_adm.credentials.tenant_id)['quota_set']
+        quota_usage = self.admin_quotas_client.show_quota_set(
+            self.os_adm.credentials.tenant_id,
+            params={'usage': True})['quota_set']
         for key in QUOTA_KEYS:
             self.assertIn(key, quota_usage)
             for usage_key in QUOTA_USAGE_KEYS:
@@ -82,15 +83,15 @@
 
     @test.idempotent_id('ae8b6091-48ad-4bfa-a188-bbf5cc02115f')
     def test_quota_usage(self):
-        quota_usage = self.admin_quotas_client.show_quota_usage(
-            self.demo_tenant_id)['quota_set']
+        quota_usage = self.admin_quotas_client.show_quota_set(
+            self.demo_tenant_id, params={'usage': True})['quota_set']
 
         volume = self.create_volume()
         self.addCleanup(self.delete_volume,
                         self.admin_volume_client, volume['id'])
 
-        new_quota_usage = self.admin_quotas_client.show_quota_usage(
-            self.demo_tenant_id)['quota_set']
+        new_quota_usage = self.admin_quotas_client.show_quota_set(
+            self.demo_tenant_id, params={'usage': True})['quota_set']
 
         self.assertEqual(quota_usage['volumes']['in_use'] + 1,
                          new_quota_usage['volumes']['in_use'])
@@ -128,11 +129,11 @@
                         self.admin_volume_client, volume['id'])
 
         # List of tenants quota usage pre-transfer
-        primary_quota = self.admin_quotas_client.show_quota_usage(
-            self.demo_tenant_id)['quota_set']
+        primary_quota = self.admin_quotas_client.show_quota_set(
+            self.demo_tenant_id, params={'usage': True})['quota_set']
 
-        alt_quota = self.admin_quotas_client.show_quota_usage(
-            self.alt_client.tenant_id)['quota_set']
+        alt_quota = self.admin_quotas_client.show_quota_set(
+            self.alt_client.tenant_id, params={'usage': True})['quota_set']
 
         # Creates a volume transfer
         transfer = self.volumes_client.create_volume_transfer(
@@ -149,11 +150,11 @@
             self.alt_client, volume['id'], 'available')
 
         # List of tenants quota usage post transfer
-        new_primary_quota = self.admin_quotas_client.show_quota_usage(
-            self.demo_tenant_id)['quota_set']
+        new_primary_quota = self.admin_quotas_client.show_quota_set(
+            self.demo_tenant_id, params={'usage': True})['quota_set']
 
-        new_alt_quota = self.admin_quotas_client.show_quota_usage(
-            self.alt_client.tenant_id)['quota_set']
+        new_alt_quota = self.admin_quotas_client.show_quota_set(
+            self.alt_client.tenant_id, params={'usage': True})['quota_set']
 
         # Verify tenants quota usage was updated
         self.assertEqual(primary_quota['volumes']['in_use'] -
diff --git a/tempest/cmd/cleanup_service.py b/tempest/cmd/cleanup_service.py
index 426571f..9758061 100644
--- a/tempest/cmd/cleanup_service.py
+++ b/tempest/cmd/cleanup_service.py
@@ -349,7 +349,8 @@
             LOG.exception("Delete Volume Quotas exception.")
 
     def dry_run(self):
-        quotas = self.client.show_quota_usage(self.tenant_id)['quota_set']
+        quotas = self.client.show_quota_set(
+            self.tenant_id, params={'usage': True})['quota_set']
         self.data['volume_quotas'] = quotas
 
 
diff --git a/tempest/services/volume/base/admin/base_quotas_client.py b/tempest/services/volume/base/admin/base_quotas_client.py
index 8528e9a..2c1f50d 100644
--- a/tempest/services/volume/base/admin/base_quotas_client.py
+++ b/tempest/services/volume/base/admin/base_quotas_client.py
@@ -42,12 +42,6 @@
         body = jsonutils.loads(body)
         return rest_client.ResponseBody(resp, body)
 
-    def show_quota_usage(self, tenant_id):
-        """List the quota set for a tenant."""
-
-        body = self.show_quota_set(tenant_id, params={'usage': True})
-        return body
-
     def update_quota_set(self, tenant_id, **kwargs):
         """Updates quota set