Otherwise the try slaves run the hooks twice, once in the apply_issue, another
in the runhooks step. It is unnecessary. It will reduce the problem with
apply_issue timeouts.

TBR=xusydoc@chromium.org
BUG=


Review URL: https://chromiumcodereview.appspot.com/11362176

git-svn-id: svn://svn.chromium.org/chrome/trunk/tools/depot_tools@166826 0039d316-1c4b-4281-b951-d872f2087c98