Make the users empty when there is no passowrd file.

scripts/master/try_job_rietveld.py

Index: scripts/master/try_job_rietveld.py
===================================================================
--- scripts/master/try_job_rietveld.py	(revision 147367)
+++ scripts/master/try_job_rietveld.py	(working copy)
@@ -65,13 +65,16 @@
       A frozenset of string containing the email addresses of users allowed to
       send jobs from Rietveld.
     """
-    pwd = open(self._PWD_FILE).readline().strip()
+    try:

[M-A Ruel, 2012/07/19 11:57:28]

I'd prefer a 
if os.path.isfile()

and be sure to log when the file is not loaded.

[Peter Mayo, 2012/07/19 19:12:52]

SGTM ... once running I'm not sure if the preferred behavior should be to
continue with the previous set, or not allow any until the permissions/contents
of the file are fixed.  Similarly for the web service being unavailable.

Did you want a third cook in this kitchen, or are you and Roger happy to
continue improvements from here?

+      pwd = open(self._PWD_FILE).readline().strip()
+    except IOError:
+      return frozenset([])
+
     now_string = str(int(time.time()))
     params = {
       'md5': hashlib.md5(pwd + now_string).hexdigest(),
       'time': now_string
     }
-
     return client.getPage('https://chromium-access.appspot.com/auto/users',
                           agent='buildbot',
                           method='POST',