The old code would always exit 0, because it returned the exit status of the if command

BUG=none
TEST=try to run git crup in src/ with unstaged changes. Should bail out and not run hooks
R=szager@chromium.org


Review URL: https://chromiumcodereview.appspot.com/12040046

git-svn-id: svn://svn.chromium.org/chrome/trunk/tools/depot_tools@178356 0039d316-1c4b-4281-b951-d872f2087c98