TEST=Run a passthru command like gcl di or gcl revert without a changelist name. Ensure that gcl exits with an error message.
BUG=none

Review URL: http://codereview.chromium.org/8413015

git-svn-id: svn://svn.chromium.org/chrome/trunk/tools/depot_tools@107663 0039d316-1c4b-4281-b951-d872f2087c98