zephyr_mirror: Ignore expired Kerberos tickets for personals mirror.

(imported from commit 094755feacd299255f078432465f11a609df9aef)

bots/zephyr_mirror_backend.py

@@ -680,6 +680,8 @@ returned the following warning:
         # just notify the user that they need to renew their tickets
         (code, stderr) = send_unauthed_zephyr(zwrite_args, wrapped_content)
         if code == 0:
+            if options.ignore_expired_tickets:
+                return
             return send_error_zulip("""%s
 
 Your last message was forwarded from Zulip to Zephyr unauthenticated, \
@@ -941,6 +943,9 @@ def parse_args():
     parser.add_option('--sync-subscriptions',
                       default=False,
                       action='store_true')
+    parser.add_option('--ignore-expired-tickets',
+                      default=False,
+                      action='store_true')
     parser.add_option('--site',
                       default=DEFAULT_SITE,
                       help=optparse.SUPPRESS_HELP)