Fix relative link in security docs.

TBR=rsesek@chromium.org

Bug: none
Change-Id: Iaf00d2457c5cde674e179d96f5d2c8852233a6dc
Reviewed-on: https://chromium-review.googlesource.com/756779
Reviewed-by: Chris Palmer <palmer@chromium.org>
Cr-Commit-Position: refs/heads/master@{#514631}
1 file changed