[PATCH 2 of 2] rust: leverage .expect() in place of .unwrap() + inline comment

[Augie Fackler]

On Mon, May 25, 2020 at 11:27:41PM +0900, Yuya Nishihara wrote:
> # HG changeset patch
> # User Yuya Nishihara <yuya at tcha.org>
> # Date 1590415610 -32400
> #      Mon May 25 23:06:50 2020 +0900
> # Node ID a5b88a7c25d3d8a02cbb2c1b9293200ddb0e06ac
> # Parent  261fbbdabb261a44c0f82537f10abbcc0d85ace1
> rust: leverage .expect() in place of .unwrap() + inline comment

queued, thanks