au_test_harness: clean up old constants reference

Use chromite.lib.constants directly since we've deleted

BUG=chromium:997354, chromium:1072917
TEST=CQ passes

Change-Id: Ie36f57085bd0eb29d821b1dbb956f8dfc6ec7a0d
Tested-by: Mike Frysinger <>
Reviewed-by: Ahmed Fakhry <>
Reviewed-by: Sean Abraham <>
Reviewed-by: Dhanya Ganesh <>
diff --git a/au_test_harness/ b/au_test_harness/
index 48d5108..c24e189 100644
--- a/au_test_harness/
+++ b/au_test_harness/
@@ -12,7 +12,6 @@
 import subprocess
 import tempfile
-from chromite.cbuildbot import constants as buildbot_constants
 from chromite.lib import constants as chromite_constants
 from chromite.lib import cros_build_lib
 from chromite.lib import cros_logging as logging
@@ -49,7 +48,7 @@
     # well as the archive stage of cbuildbot. Make a private copy of
     # the VM image, to avoid any conflict.
     _, private_image_path = tempfile.mkstemp(
-        prefix='%s.' % buildbot_constants.VM_DISK_PREFIX)
+        prefix='%s.' % chromite_constants.VM_DISK_PREFIX)
     shutil.copy(self.vm_image_path, private_image_path)
     self.TestInfo('Copied shared disk image %s to %s.' %
                   (self.vm_image_path, private_image_path))