fix goimports whitespace
fix goimports whitespace

Ran goimports -w client/ to fix a travis-ci failure.

R=maruel@chromium.org
BUG=

Review URL: https://codereview.chromium.org/1100333005

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