upload_prebuilts: Drop support for legacy XML format for GS ACL file.

The legacy XML format for the Google Storage ACL file is not longer supported.
All the overlays have migrated to using a different format. Drop support for
this file in chromite.

BUG=chromium:424325
TEST=unittests.

Change-Id: I52ed8d9f0bcc89a5764f7f125c56a0972cd4e110
Reviewed-on: https://chromium-review.googlesource.com/224168
Reviewed-by: Mike Frysinger <vapier@chromium.org>
Commit-Queue: Prathmesh Prabhu <pprabhu@chromium.org>
Tested-by: Prathmesh Prabhu <pprabhu@chromium.org>
diff --git a/scripts/upload_prebuilts_unittest.py b/scripts/upload_prebuilts_unittest.py
index ed389c0..d63f6e8 100755
--- a/scripts/upload_prebuilts_unittest.py
+++ b/scripts/upload_prebuilts_unittest.py
@@ -424,7 +424,7 @@
     prebuilt.GetBoardOverlay(
         options.build_path, options.board).AndReturn(fake_overlay_path)
     expected_gs_acl_path = os.path.join(fake_overlay_path,
-                                        prebuilt._GOOGLESTORAGE_ACL_FILE)
+                                        prebuilt._GOOGLESTORAGE_GSUTIL_FILE)
     prebuilt.PrebuiltUploader.__init__(options.upload, expected_gs_acl_path,
                                        options.upload, mox.IgnoreArg(),
                                        options.build_path, options.packages,