This CL prevents map-branches from loading the tracking status when
the -v flag is not supplied. This prevents the vanilla map-branches
from taking a potentially long time to retrieve the tracking status.

BUG=410137

Review URL: https://codereview.chromium.org/536793002

git-svn-id: svn://svn.chromium.org/chrome/trunk/tools/depot_tools@291846 0039d316-1c4b-4281-b951-d872f2087c98