pass pylint cleanly.

There should be no functional changes in this patch, although there's at least one minor bug that lint caught.

Review URL: http://codereview.chromium.org/6685023

git-svn-id: svn://svn.chromium.org/chrome/trunk/tools/depot_tools@78638 0039d316-1c4b-4281-b951-d872f2087c98