Remove eugenebut from ios/chrome/browser/download owners

Bug: None
Change-Id: I17ffab718b09776455fe8a0220df49803e36755c
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2633976
Commit-Queue: Eugene But <eugenebut@chromium.org>
Auto-Submit: Eugene But <eugenebut@chromium.org>
Reviewed-by: Sylvain Defresne <sdefresne@chromium.org>
Cr-Commit-Position: refs/heads/master@{#845711}

ios/chrome/browser/download/OWNERS

-eugenebut@chromium.org
-sdefresne@chromium.org