patch: upgraded package to upstream

Upgraded sys-devel/patch to version 2.7.4 for security fixes.

BUG=None
TEST=`cbuildbot chromiumos-sdk` passes

Change-Id: Icf7fef511426d7817f4dc8fa2bb823d7c617d939
Reviewed-on: https://chromium-review.googlesource.com/250151
Reviewed-by: Nam Nguyen <namnguyen@chromium.org>
Tested-by: Mike Frysinger <vapier@chromium.org>
Commit-Queue: Mike Frysinger <vapier@chromium.org>
3 files changed