Set close_fds True in Popen of cloudtail

scripts/slave/recipe_modules/goma/resources/cloudtail_utils.py

 #!/usr/bin/env python
 # Copyright (c) 2016 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.
 
 import argparse
 import errno
 import os
 import signal
 import subprocess
 import sys
 
 from slave import goma_utils
 
 
 def start_cloudtail(args):
   """Write process id of started cloudtail to file object f"""
 
   proc = subprocess.Popen([args.cloudtail_path,
                            'tail',
                            '--log-id', 'goma_compiler_proxy',
                            '--path',
-                           goma_utils.GetLatestGomaCompilerProxyInfo()])
+                           goma_utils.GetLatestGomaCompilerProxyInfo()],
+                          stdout=open(os.devnull, 'w'),
+                          stderr=open(os.devnull, 'w'),
+                          close_fds=True)
 
   sys.stdout.write(str(proc.pid))
 
 
 def main():
   parser = argparse.ArgumentParser(
       description='cloudtail utility for goma recipe module.')
 
   subparsers = parser.add_subparsers(help='commands for cloudtail')
 
@@ skipping 17 matching lines @@
     try:
       os.kill(args.killed_pid, signal.SIGKILL)
     except OSError as e:
       if e.errno != errno.ESRCH:
         # TODO(tikuta): Resolve https://crbug.com/639910.
         raise
 
 
 if '__main__' == __name__:
   sys.exit(main())