[Machine Database] Report pRPC tsmon metrics
[Machine Database] Report pRPC tsmon metrics

Bug: 778865
Change-Id: I4292be47ced90264b02c85a54bc8ac8540d15701
Reviewed-on: https://chromium-review.googlesource.com/979168
Reviewed-by: Nodir Turakulov <ef4933a197ef7b4b3f55f1bec4942aead3637a2a@chromium.org>
Commit-Queue: smut <95deb7aa15d4c615299e47e7688551456568b1fb@google.com>

luci/luci-go,luci/luci-go,luci/luci-go,luci/luci-go,luci/luci-go,luci/luci-go