Delete dead "Blame" action in garden-o-matic

I never finished implementing this feature. It's not used.

R=esprehn@chromium.org
BUG=387412
NOTRY=true

Review URL: https://codereview.chromium.org/343653010

git-svn-id: svn://svn.chromium.org/blink/trunk@176816 bbb929c8-8fbe-4397-9dbb-9b2b20218538