Remove attotech.net from the HSTS preload list.

The site operator believes that they never requested to be added.
It's still unclear how they ended up on the list unintentionally, since
they were added through hstspreload.appspot.com (which requires sending
an explicit `preload` token in an HSTS header from the root path).

BUG=527947
TBR=agl@chromium.org

Review URL: https://codereview.chromium.org/1520993002

Cr-Commit-Position: refs/heads/master@{#364828}
2 files changed