client: rename delete_and_upload to upload_then_delete
client: rename delete_and_upload to upload_then_delete

This is for
https://chromium-review.googlesource.com/c/infra/luci/luci-go/+/1802061/9/cmdrunner/command.go#260

Bug: 962804
Change-Id: I85bd143fa14481e530700c2c958f35299fabec8f
Reviewed-on: https://chromium-review.googlesource.com/c/infra/luci/luci-py/+/1806636
Reviewed-by: Junji Watanabe <aaef61ef98ffea505db831f310be2a0eb8492537@google.com>
Commit-Queue: Takuto Ikuta <71927f930fca81015e0f496c65cd126ab1a692e3@chromium.org>
Auto-Submit: Takuto Ikuta <71927f930fca81015e0f496c65cd126ab1a692e3@chromium.org>

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