Remove an unused variable.

Bug: 775328
Change-Id: I96c860f729c58d3dff9893255978f72eb2bb448b
Reviewed-on: https://chromium-review.googlesource.com/727039
Commit-Queue: Nico Weber <thakis@chromium.org>
Reviewed-by: Dale Curtis <dalecurtis@chromium.org>
Cr-Commit-Position: refs/heads/master@{#509917}