parsedate_tz(): Be slightly more lenient when there's no day of the

week.  Patch given by Daniel Berlin in SF bug # 732761.  Also closes
SF bug # 727719.

Backport candidate.

Lib/email/_parseaddr.py

@@ -54,9 +54,8 @@ def parsedate_tz(data):
         del data[0]
     else:
         i = data[0].rfind(',')
-        if i < 0:
-            return None
-        data[0] = data[0][i+1:]
+        if i >= 0:
+            data[0] = data[0][i+1:]
     if len(data) == 3: # RFC 850 date, deprecated
         stuff = data[0].split('-')
         if len(stuff) == 3: