Fsync directory contents am: bcc64c495a

Original change: https://android-review.googlesource.com/c/platform/system/update_engine/+/3056642

Change-Id: I809c9dc13e4dc93fdf4c9efe1d2cd99e08b5b673
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>