tricium.config: delete unused file

The service has been turned down, so no need for the config anymore.

Change-Id: Ie7108b2be26e437cdb631e78333d6fb708c815b9
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/+/7205555
Reviewed-by: Yiwei Zhang <yiwzhang@google.com>