Refactor acloud.public.errors to acloud.errors.

Bug: 113753798
Test: atest acloud_test && run acloud create/list/delete
Change-Id: I03b4b34769d754bfebd279895b0ca44311bbecc7
diff --git a/internal/lib/gstorage_client.py b/internal/lib/gstorage_client.py
index b309903..586b173 100755
--- a/internal/lib/gstorage_client.py
+++ b/internal/lib/gstorage_client.py
@@ -20,9 +20,9 @@
 
 import apiclient
 
+from acloud import errors
 from acloud.internal.lib import base_cloud_client
 from acloud.internal.lib import utils
-from acloud.public import errors
 
 logger = logging.getLogger(__name__)