Fix commit queue to actually abort on import error. BUG=306111 R=phajdan.jr@chromium.org,iannucci@chromium.org,vadimsh@chromium.org Review URL: https://codereview.chromium.org/26933002 git-svn-id: svn://svn.chromium.org/chrome/trunk/tools/commit-queue@228037 0039d316-1c4b-4281-b951-d872f2087c98