Get rid of GetPreferredTryMasters that just loads cq.cfg.

git cl try now schedules CQ dry run by default.

BUG=577224
R=sergiyb@chromium.org,phajdan.jr@chromium.org

Review-Url: https://codereview.chromium.org/2151543002
Cr-Commit-Position: refs/heads/master@{#405218}
1 file changed