Change auto-roll to auto-push for automatic trunk pushes.

The current script is only performing automatic pushes to trunk. This prepares for adding an auto-roll script that actually rolls to Chromium.

This also removes the v8-status updates, which are no longer necessary due to not touching bleeding edge any more.

BUG=
R=jarin@chromium.org

Review URL: https://codereview.chromium.org/196173018

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@20205 ce2b1a6d-e550-0410-aec6-3dcde31c8c00