Revert "swarming_bot: send ping request to server in CMDis_infe"
Revert "swarming_bot: send ping request to server in CMDis_infe"

This reverts commit 2ce25539b8b4df0e15662248481663505ba8cf90.

Reason for revert: speculative revert for http://screen/qm8PzpFhxD7

Original change's description:
> swarming_bot: send ping request to server in CMDis_infe
> 
> This just follows crbug.com/971721#c10
> 
> Bug: 971721
> Change-Id: I3235392a5b2454ce8b51f6e20fb07b5e6d90d813
> Reviewed-on: https://chromium-review.googlesource.com/c/infra/luci/luci-py/+/1835431
> Commit-Queue: Takuto Ikuta <71927f930fca81015e0f496c65cd126ab1a692e3@chromium.org>
> Reviewed-by: Junji Watanabe <jwata@google.com>
> Auto-Submit: Takuto Ikuta <71927f930fca81015e0f496c65cd126ab1a692e3@chromium.org>

TBR=maruel@chromium.org,71927f930fca81015e0f496c65cd126ab1a692e3@chromium.org,jwata@google.com

Change-Id: I01e55a8dbb5e0110dea78ef61c90b6de897c3d9f
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug: 971721
Reviewed-on: https://chromium-review.googlesource.com/c/infra/luci/luci-py/+/1835831
Reviewed-by: Takuto Ikuta <71927f930fca81015e0f496c65cd126ab1a692e3@chromium.org>
Commit-Queue: Takuto Ikuta <71927f930fca81015e0f496c65cd126ab1a692e3@chromium.org>

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