Make update_prebilts.py fail gracefully on bad sdk zip am: a26e481a43 am: 7f43612981 am: 3a63caac09

Original change: https://googleplex-android-review.googlesource.com/c/platform/prebuilts/sdk/+/10830938

Change-Id: Ic9f0d911b799ef616492686f8c4008e8ab1df624