Also fix argument processing.

It doesn't works at the moment but doesn't throw an exception either. :)

TEST=none
BUG=none

Review URL: http://codereview.chromium.org/125095

git-svn-id: svn://svn.chromium.org/chrome/trunk/tools/depot_tools@18611 0039d316-1c4b-4281-b951-d872f2087c98