fix update_engine warnings am: a75d5cbc92

Original change: https://android-review.googlesource.com/c/platform/system/update_engine/+/3419439

Change-Id: I34dca0c2d3a14fa6a7750b4424b58fa033fc6529
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>