Remove unused imports and fix some other linter errors.

recipes.py

 #!/usr/bin/env python
 # Copyright 2015 The LUCI Authors. All rights reserved.
 # Use of this source code is governed under the Apache License, Version 2.0
 # that can be found in the LICENSE file.
 
 """Tool to interact with recipe repositories.
 
 This tool operates on the nearest ancestor directory containing an
 infra/config/recipes.cfg.
 """
 
 import argparse
 import json
 import logging
 import os
 import shutil
 import subprocess
 import sys
 import tempfile
 
 ROOT_DIR = os.path.dirname(os.path.abspath(__file__))
 sys.path.insert(0, ROOT_DIR)
 
 from recipe_engine import env
 from recipe_engine import arguments_pb2
 from google.protobuf import json_format as jsonpb
-from google.protobuf import text_format as textpb
+
 
 def get_package_config(args):
   from recipe_engine import package
 
   assert args.package, 'No recipe config (--package) given.'
   assert os.path.exists(args.package), (
       'Given recipes config file %s does not exist.' % args.package)
   return (
       package.InfraRepoConfig().from_recipes_cfg(args.package),
       package.ProtoFile(args.package)
@@ skipping 694 matching lines @@
 
   if not isinstance(ret, int):
     if ret is None:
       ret = 0
     else:
       print >> sys.stderr, ret
       ret = 1
   sys.stdout.flush()
   sys.stderr.flush()
   os._exit(ret)