Remove unnecessary call to truncate() am: 8436f18976 am: 8e91bd5cf9

Original change: https://android-review.googlesource.com/c/platform/system/update_engine/+/2320955

Change-Id: I1fb521b4df53c5e33855fa59beba6791aea4c514
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>