Fix crash on ota_extractor am: 93e3810b0c

Original change: https://android-review.googlesource.com/c/platform/system/update_engine/+/2063610

Change-Id: Ia6842c12ac3eacf21e53239d3319b5392c9a2ca6
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>