[Machine Provider] Convert agent to use webapp2 routes
[Machine Provider] Convert agent to use webapp2 routes

Bug: 805543
Change-Id: I8889bbe48113f18371ba6ab37c6576f58cbf2786
Reviewed-on: https://chromium-review.googlesource.com/1043386
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