Internal teams are relying on git-try as the sole mean to run try jobs so revert
this.

Hopefully most target users (chromium folks) got the message at least once.

R=cmp@chromium.org
BUG=

Review URL: https://codereview.chromium.org/88743003

git-svn-id: svn://svn.chromium.org/chrome/trunk/tools/depot_tools@237361 0039d316-1c4b-4281-b951-d872f2087c98