Roll infra/go/src/github.com/luci/luci-go 51ea47e
Roll infra/go/src/github.com/luci/luci-go 51ea47e

https://github.com/luci/luci-go/compare/e002f6a3d0d512daca7db08849eda7093493f2ef...51ea47eddf0ca3349c42c2f33c266053fe5ca44e

R=vadimsh@chromium.org
BUG=498467

Review URL: https://codereview.chromium.org/1334013002

nicko96/Chrome-Infra,nicko96/Chrome-Infra,nicko96/Chrome-Infra,nicko96/Chrome-Infra,nicko96/Chrome-Infra