[swarming] log content of path when we see UnicodeDecodeError
[swarming] log content of path when we see UnicodeDecodeError

Apply ord to make sure byte sequence are shown.

Bug: 1039746
Change-Id: I77cd029604231dafffa2ec74e892a711841ed994
Reviewed-on: https://chromium-review.googlesource.com/c/infra/luci/luci-py/+/1990918
Auto-Submit: Takuto Ikuta <71927f930fca81015e0f496c65cd126ab1a692e3@chromium.org>
Reviewed-by: Junji Watanabe <aaef61ef98ffea505db831f310be2a0eb8492537@google.com>
Commit-Queue: Takuto Ikuta <71927f930fca81015e0f496c65cd126ab1a692e3@chromium.org>

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