Remove autoinstaller code from webkitpy (no longer needed!).

R=ojan@chromium.org
BUG=230706

Review URL: https://codereview.chromium.org/19696004

git-svn-id: svn://svn.chromium.org/blink/trunk@154468 bbb929c8-8fbe-4397-9dbb-9b2b20218538