Fix T110 violations for image_client

image_client contained T110 violations, and we need to fix them
before migrating the client to tempest-lib for consistent interfaces.

Partially implements blueprint consistent-service-method-names

Change-Id: I376efbc703762473ab69bfe424064bf32c4e78a5
diff --git a/tempest/api/image/admin/v2/test_images.py b/tempest/api/image/admin/v2/test_images.py
index 01838b6..b171da3 100644
--- a/tempest/api/image/admin/v2/test_images.py
+++ b/tempest/api/image/admin/v2/test_images.py
@@ -49,12 +49,12 @@
         body = self.client.show_image(image_id)
         self.assertEqual("deactivated", body['status'])
         # non-admin user unable to download deactivated image
-        self.assertRaises(lib_exc.Forbidden, self.client.load_image_file,
+        self.assertRaises(lib_exc.Forbidden, self.client.show_image_file,
                           image_id)
         # reactivate image
         self.admin_client.reactivate_image(image_id)
         body = self.client.show_image(image_id)
         self.assertEqual("active", body['status'])
         # non-admin user able to download image after reactivation by admin
-        body = self.client.load_image_file(image_id)
+        body = self.client.show_image_file(image_id)
         self.assertEqual(content, body.data)