[milo] remove datastore cursors from buildbot
[milo] remove datastore cursors from buildbot

The new numeric cursors were added last week. Presumably,
nobody needs datastore cursors, so delete them.

Bug: 772696
Change-Id: I49fd4c75c145bf7edfdf18419a74efa653bd19a0
Reviewed-on: https://chromium-review.googlesource.com/710515
Commit-Queue: Nodir Turakulov <ef4933a197ef7b4b3f55f1bec4942aead3637a2a@chromium.org>
Reviewed-by: Robbie Iannucci <40f3d43a28ebae3cb819288542e1c84d73d962d5@chromium.org>

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