Auto detect minor version for complete partial updates am: 2a18e85a31 am: 618a20ff2b

Original change: https://android-review.googlesource.com/c/platform/system/update_engine/+/2770381

Change-Id: I9917d20117187d0f75f807bec576514b14de6636
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>