Fix assertion error on unclean master shutdown

Commit 66bd7445 added an assertion to ensure a finalized job has its
“end_timestamp” attribute set. Unfortunately it didn't cover a case when
the queue is recovering from an unclean master shutdown.

Signed-off-by: Michael Hanselmann <hansmi@google.com>
Reviewed-by: Iustin Pop <iustin@google.com>
Reviewed-by: René Nussbaumer <rn@google.com>
(cherry picked from commit 45df0793)

lib/jqueue.py

@@ -1289,6 +1289,7 @@ class JobQueue(object):
         else:
           job.MarkUnfinishedOps(constants.OP_STATUS_ERROR,
                                 "Unclean master daemon shutdown")
+          job.Finalize()
 
         self.UpdateJobUnlocked(job)