Move recipe engine to third_party/recipe_engine.

scripts/slave/recipe_modules/tryserver/api.py

 # Copyright 2014 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 contextlib
 import hashlib
 
-from slave import recipe_api
+from recipe_engine import recipe_api
 
 
 PATCH_STORAGE_RIETVELD = 'rietveld'
 PATCH_STORAGE_GIT = 'git'
 PATCH_STORAGE_SVN = 'svn'
 
 
 class TryserverApi(recipe_api.RecipeApi):
   def __init__(self, *args, **kwargs):
     super(TryserverApi, self).__init__(*args, **kwargs)
@@ skipping 200 matching lines @@
       self.add_failure_reason(e.reason)
 
       failure_hash = hashlib.sha1()
       failure_hash.update(self.m.json.dumps(self._failure_reasons))
 
       step_result = self.m.step.active_result
       step_result.presentation.properties['failure_hash'] = \
           failure_hash.hexdigest()
 
       raise