Milo: Fix url for internal builds
Milo: Fix url for internal builds

BUG=
TBR=nodir

Review-Url: https://codereview.chromium.org/2484863006

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