Fixed slight bug in CMDpassthru where the command name was being passed to the CL Load rather than the CL name.

TEST=Try passthru commands like gcl revert and gcl stat and ensure that they perform as expected on each file in a CL.
BUG=none

Review URL: http://codereview.chromium.org/8404044

git-svn-id: svn://svn.chromium.org/chrome/trunk/tools/depot_tools@107576 0039d316-1c4b-4281-b951-d872f2087c98