Add option to create a "Bug:" line in commit messages. am: 90784f32d5

Original change: https://android-review.googlesource.com/c/platform/packages/modules/ArtPrebuilt/+/1594253

MUST ONLY BE SUBMITTED BY AUTOMERGER

Change-Id: Ic0315a68b945f9cb5a8baca69dca7a008fde40ad