devserver: Fix lint issues.

Fix many (not all) lint issues in this directory.

BUG=None
TEST=run_unittests

Change-Id: Ifc934808c02aef45243e6a6ed099124cca4674d2
Reviewed-on: https://chromium-review.googlesource.com/354735
Commit-Ready: Don Garrett <dgarrett@chromium.org>
Tested-by: Don Garrett <dgarrett@chromium.org>
Reviewed-by: Ningning Xia <nxia@chromium.org>
diff --git a/build_util.py b/build_util.py
index 29c408b..0e8f680 100644
--- a/build_util.py
+++ b/build_util.py
@@ -2,13 +2,16 @@
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
+"""Defines a build related helper class."""
+
+from __future__ import print_function
+
 import os
 import sys
 
 
 class BuildObject(object):
-  """
-  Common base class that defines key paths in the source tree.
+  """Common base class that defines key paths in the source tree.
 
   Classes that inherit from BuildObject can access scripts in the src/scripts
   directory, and have a handle to the static directory of the devserver.