Reduce frequency of sync() in update_engine logging am: d2a298df41

Original change: https://android-review.googlesource.com/c/platform/system/update_engine/+/2895963

Change-Id: I1b5ecee4e40d8d1e8254da0d01c13f17deab179e
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>