Tiny updates to trychange_git. The actual refs will be "refs/tryjobs/blah" to mirror ChromeOS's system. R=iannucci@chromium.org Review URL: https://chromiumcodereview.appspot.com/23452051 git-svn-id: svn://svn.chromium.org/chrome/trunk/tools/chromium-jobqueue@224540 0039d316-1c4b-4281-b951-d872f2087c98