go.tools/dashboard/app: fix integration tests
go.tools/dashboard/app: fix integration tests

They had been broken after a few recent changes.

LGTM=bradfitz
R=bradfitz
CC=golang-codereviews
https://codereview.appspot.com/152150043

karmakaze/go.tools,karmakaze/go.tools,karmakaze/go.tools,karmakaze/go.tools,karmakaze/go.tools