Ensure partitions are at least 1 block in size am: 316e7c01c1 am: 5c4b29f432 am: f37dc1429c

Original change: https://android-review.googlesource.com/c/platform/system/update_engine/+/2759626

Change-Id: I2f712424b7a760e96781c339df54e665b8c29678
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>