python-single-r1.eclass: Upgrade to upstream

This CL upgraded to upstream commit :
4685a5f4ed0eb025a4fdb5d5b913357ef077b728.

Needed for `PYTHON_MULTI_USEDEP` keywords in zbar.ebuild.

BUG=b:154521931
TEST=emerge-board media-gfx/zbar success
TEST=update_chroot

Change-Id: I9809b616ebd73c8f7f10619cbb2455582322fb79
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/overlays/portage-stable/+/2169947
Reviewed-by: Mike Frysinger <vapier@chromium.org>
Commit-Queue: Yilin Yang (kerker) <kerker@chromium.org>
Tested-by: Yilin Yang (kerker) <kerker@chromium.org>
1 file changed