client: implement retry for archive_files_to_storage
client: implement retry for archive_files_to_storage

This implements workaround in crbug.com/1073832#c11

I confirmed it is possible that leaked process doesn't run more than 100
seconds with
crrev.com/c/2167746
on
https://chromium-swarm.appspot.com/task?id=4bd79747bac89810

Bug: 1073832
Change-Id: Icbe704fa8946d18928e948f751e8ca20943720bd
Reviewed-on: https://chromium-review.googlesource.com/c/infra/luci/luci-py/+/2169528
Commit-Queue: Takuto Ikuta <71927f930fca81015e0f496c65cd126ab1a692e3@chromium.org>
Reviewed-by: Junji Watanabe <aaef61ef98ffea505db831f310be2a0eb8492537@google.com>
Auto-Submit: Takuto Ikuta <71927f930fca81015e0f496c65cd126ab1a692e3@chromium.org>

luci/luci-py,luci/luci-py,luci/luci-py,luci/luci-py