This brings back git cl try to try at LKGR instead of HEAD, which is coherent
with git-try and gcl try.

R=rogerta@chromium.org
BUG=


Review URL: https://chromiumcodereview.appspot.com/10963013

git-svn-id: svn://svn.chromium.org/chrome/trunk/tools/depot_tools@157810 0039d316-1c4b-4281-b951-d872f2087c98