resolve rust clippy 1.50 issues

The issue was with unnecessary lifetimes and nested match statements
that resolved quite cleanly in this change.

BUG=b:179277332
TEST=cargo clippy with rustc 1.50+

Change-Id: Ibbac7a46e2209d8262a2bd5d205b23793e096017
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/third_party/adhd/+/2757729
Auto-Submit: Zach Reizner <zachr@chromium.org>
Reviewed-by: Dylan Reid <dgreid@chromium.org>
Commit-Queue: Zach Reizner <zachr@chromium.org>
Tested-by: Zach Reizner <zachr@chromium.org>
2 files changed