Cleanup most pylint errors in json_schema_compiler.

tools/json_schema_compiler/features_compiler.py

 #!/usr/bin/env python
 # Copyright 2013 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 """Generator for C++ features from json files.
 
 Usage example:
   features_compiler.py --destdir gen --root /home/Work/src _permissions.json
 """
 
 import optparse
 import os
 
 from schema_loader import SchemaLoader
 from features_cc_generator import CCGenerator
 from features_h_generator import HGenerator
 from model import CreateFeature
 
 
 def _GenerateSchema(filename, root, destdir, namespace):
   """Generates C++ features files from the json file |filename|.
   """
   # Load in the feature permissions from the JSON file.
   schema = os.path.normpath(filename)
   schema_loader = SchemaLoader(os.path.dirname(os.path.relpath(schema, root)),
-    os.path.dirname(schema))
+                               os.path.dirname(schema),
+                               [],
+                               None)
   schema_filename = os.path.splitext(schema)[0]
   feature_defs = schema_loader.LoadSchema(schema)
 
   # Generate a list of the features defined and a list of their models.
   feature_list = []
   for feature_def, feature in feature_defs.iteritems():
     feature_list.append(CreateFeature(feature_def, feature))
 
   source_file_dir, _ = os.path.split(schema)
   relpath = os.path.relpath(os.path.normpath(source_file_dir), root)
@@ skipping 30 matching lines @@
   (opts, filenames) = parser.parse_args()
 
   # Only one file is currently specified.
   if len(filenames) != 1:
     raise ValueError('One (and only one) file is required (for now).')
 
   result = _GenerateSchema(filenames[0], opts.root, opts.destdir,
                            opts.namespace)
   if not opts.destdir:
     print result