Change the builder links to point to the earliest failing build.

This shows when the failure started, which is more useful than just
showing the builder's waterfall page.

While I"m in the code, remove the unused steps parameter of ct-builder
and move the input to ct-builder to be a CTBuilder model object.

NOTRY=true

Review URL: https://codereview.chromium.org/426603003

git-svn-id: svn://svn.chromium.org/blink/trunk@179659 bbb929c8-8fbe-4397-9dbb-9b2b20218538