[Machine Database] Allow read access to FindVMSlots, non-admin write access to all APIs
[Machine Database] Allow read access to FindVMSlots, non-admin write access to all APIs

Change-Id: Ibbd05e0b656002844eaeba3bfbb6d57f8c801ed6
Reviewed-on: https://chromium-review.googlesource.com/1069673
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