aosp: remove gclient flag --delete_unversioned_trees Suggested by Gerrit folks: b/305091097#comment13 This flag has been set for a long time, but after migration to submodules it might be causing trouble. Bug: b/305091097 Change-Id: I9eba5bf4ebe192942ab72b7670628f957b03ecc6 Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/5077411 Auto-Submit: Roman Lavrov <romanl@google.com> Reviewed-by: Yuly Novikov <ynovikov@chromium.org>