Fix hard-coded path in infra PRESUBMIT.py.
Fix hard-coded path in infra PRESUBMIT.py.

R=agable@chromium.org
BUG=

Review URL: https://codereview.chromium.org/437713002

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