Remove --bootstrap-script parameter from recipes.py

recipes.py

 #!/usr/bin/env python
 
 # Copyright 2016 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.
 
 """Bootstrap script to clone and forward to the recipe engine tool.
 
 ***********************************************************************
 ** DO NOT MODIFY EXCEPT IN THE PER-REPO CONFIGURATION SECTION BELOW. **
@@ skipping 143 matching lines @@
 
   try:
     ensure_engine()
   except subprocess.CalledProcessError:
     logging.exception('ensure_engine failed')
 
     # Retry errors.
     time.sleep(random.uniform(2,5))
     ensure_engine()
 
-  args = ['--package', recipes_cfg_path,
-          '--bootstrap-script', __file__] + sys.argv[1:]
+  args = ['--package', recipes_cfg_path] + sys.argv[1:]
   return _subprocess_call([
       sys.executable, '-u',
       os.path.join(engine_path, engine_subpath, 'recipes.py')] + args)
 
 if __name__ == '__main__':
   sys.exit(main())