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/utils_test.py b/internal/lib/utils_test.py
index 9225ddd..79c1c6d 100644
--- a/internal/lib/utils_test.py
+++ b/internal/lib/utils_test.py
@@ -27,9 +27,9 @@
 import unittest
 import mock
 
+from acloud import errors
 from acloud.internal.lib import driver_test_lib
 from acloud.internal.lib import utils
-from acloud.public import errors
 
 # Tkinter may not be supported so mock it out.
 try: