Fix cros lint issues in chromite/scripts.

Fix or disable all cros lint warnings in scripts.

BUG=None
TEST=Ran pylint.

Change-Id: Iedd2f2e361ea82c082f1c95c9054ac15d19193ff
Reviewed-on: https://chromium-review.googlesource.com/190730
Reviewed-by: Don Garrett <dgarrett@chromium.org>
Tested-by: Don Garrett <dgarrett@chromium.org>
Commit-Queue: Don Garrett <dgarrett@chromium.org>
diff --git a/scripts/cros.py b/scripts/cros.py
index 45470a4..8d49d04 100644
--- a/scripts/cros.py
+++ b/scripts/cros.py
@@ -2,6 +2,17 @@
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
+"""This implements the metacommand cros.
+
+This script is normally invoked via depot_tools/cros which discovers
+where chromite is located and invokes this script.
+
+In turn, this script looks for a subcommand based on how it was invoked. For
+example: cros lint.
+
+See cros/command/cros_XXX.py for actual command implementations.
+"""
+
 import sys
 
 from chromite.cros import commands