Prevent non-admin users from deleting system apps. am: 6c870e15 am: 15ab50ec

Original change: https://googleplex-android-review.googlesource.com/c/platform/frameworks/base/+/17408864



Change-Id: Ie4d1088736fb3f99d8f8a20c9cf1e8eb87a674cd
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>