This is best-effort only; s390x is still not a supported platform.

CIPD pin bump contains no client changes; just points to a version
which is built for s390x as well our normal platforms.

R=dnj@chromium.org, vadimsh@chromium.org

Bug: 764087
Change-Id: I777246712eea1b39036f3b14b88cbd41c7cf0507
Reviewed-on: https://chromium-review.googlesource.com/661787
Commit-Queue: Robbie Iannucci <iannucci@chromium.org>
Reviewed-by: Vadim Shtayura <vadimsh@chromium.org>