constantly: upgraded package to upstream

Upgraded dev-python/constantly to version 15.1.0-r1 on amd64, arm

It's need by twisted.

BUG=chromium:999876
TEST=update_chroot

Change-Id: I55abd3c4409488c68efb8f4982c8192901cd727b
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/overlays/portage-stable/+/2212083
Reviewed-by: Mike Frysinger <vapier@chromium.org>
Tested-by: Yilin Yang (kerker) <kerker@chromium.org>
Commit-Queue: Yilin Yang (kerker) <kerker@chromium.org>
4 files changed