The new version uses SHA256 for uploads by default. It also fully supports
$ResolvedVersions and 'selfupdate-roll'.

The roll was generated by:
$ ./cipd selfupdate-roll \
  -version-file cipd_client_version \
  -version git_revision:fb963f0f43e265a65fb7f1f202e17ea23e947063

BUG=821194, 870166
R=nodir@chromium.org, iannucci@chromium.org

Change-Id: If7c23c43ff2c1bf50c9c50f4e9e17a23e84859b9
Reviewed-on: https://chromium-review.googlesource.com/1227431
Commit-Queue: Vadim Shtayura <vadimsh@chromium.org>
Reviewed-by: Nodir Turakulov <nodir@chromium.org>