message: drakefile: Fix warning disablement.
diff: @@ -49,7 +49,7 @@ def configure(cxx_toolkit,
  local_config = drake.cxx.Config(config)
  local_config.add_local_include_path('sys')
  local_config.add_local_include_path('dokan')
  - local_config.warnings.sign_compare = None
  + local_config.warnings.sign_compare = False
  local_config.warnings.missing_declarations = None
  local_config.define('UNICODE')
  local_config.define('_UNICODE')
  