recipe_autoroller: always set cwd to workdir

recipes/recipe_modules/recipe_autoroller/api.py

 # Copyright 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 base64
 import hashlib
 import json
 import re
 
 from recipe_engine import recipe_api
@@ skipping 161 matching lines @@
       # Introduce ourselves to git - also needed for git cl upload to work.
       self.m.git(
           'config', 'user.email', 'recipe-roller@chromium.org', cwd=workdir)
       self.m.git('config', 'user.name', 'recipe-roller', cwd=workdir)
 
       # git cl upload cannot work with detached HEAD, it requires a branch.
       self.m.git('checkout', '-t', '-b', 'roll', 'origin/master', cwd=workdir)
 
       # Check status of last known CL for this repo. Ensure there's always
       # at most one roll CL in flight.
-      repo_data, cl_status = self._get_pending_cl_status(
-          project_data['repo_url'])
+      with self.m.step.context({'cwd': workdir}):
+        repo_data, cl_status = self._get_pending_cl_status(
+            project_data['repo_url'])
       if repo_data:
         # Allow trivial rolls in CQ to finish.
         if repo_data['trivial'] and cl_status == 'commit':
           return ROLL_SUCCESS
 
         # Allow non-trivial rolls to wait for review comments.
         if not repo_data['trivial'] and cl_status != 'closed':
           return ROLL_SUCCESS
 
         # We're about to upload a new CL, so close the old one.
@@ skipping 174 matching lines @@
         'cl', 'status',
         '--issue', repo_data['issue'],
         '--rietveld',
         '--field', 'status',
         name='git cl status', stdout=self.m.raw_io.output(),
         step_test_data=lambda: self.m.raw_io.test_api.stream_output(
             'foo')
     ).stdout.strip()
 
     return repo_data, status_result