pylint: upgrade to 1.3.1

The current pylint is very old at this point.  Pull in the latest version
as it supports a lot more features.  Also need to fix the pylint wrapper
to actually update sys.path to use the local modules.

We include the six module since not all bots have it, and it's small.

This will trigger new warnings in files, but they look like legitimate
issues that should be fixed at some point.

BUG=chromium:431514
TEST=ran on some code bases and checked output

Review URL: https://codereview.chromium.org/741503002

git-svn-id: http://src.chromium.org/chrome/trunk/tools/depot_tools@292988 4ff67af0-8c30-449e-8e8b-ad334ec8d88c
disable new pylint warnings

People are just ignoring these and bypassing the presubmit entirely, so
disable all the warnings until someone feels like shaving these yaks one
by one.

BUG=chromium:431514
TEST=ran presubmit on build/ and so no more warnings

Review URL: https://codereview.chromium.org/721833003

git-svn-id: http://src.chromium.org/chrome/trunk/tools/depot_tools@292997 4ff67af0-8c30-449e-8e8b-ad334ec8d88c