message: Fix redex.py, config may be empty
  Summary:
  An issue from github :
  The issue is introduced by
diff: @@ -720,7 +720,7 @@ def finalize_redex(state):
  state.dex_dir,
  state.args.proguard_map)
  else:
  - passes_list = state.config_dict['redex']['passes']
  + passes_list = state.config_dict.get('redex', {}).get('passes', [])
  assert 'RenameClassesPass' not in passes_list and\
  'RenameClassesPassV2' not in passes_list
  