[automerger skipped] Record the source build fingerprint in SnapshotMergeStats. am: e2b83494b3 -s ours

am skip reason: Merged-In I27cdc72272a9fa4ff5df4968e200fc14f63d0146 with SHA-1 4657407a32 is already in history

Original change: https://googleplex-android-review.googlesource.com/c/platform/system/update_engine/+/15178752

Change-Id: I80f73d35c117a2e7ed2f8f7a39054ee0e64def7f