ingest_mdir: wait for workers to actually do something

Since the removal of barriers, this just queues the work
and then stops it, without ever doing it. Fix that.

Fixes: fd7d03f ("stop using barriers")
Signed-off-by: Johannes Berg <[email protected]>

Author: jmberg

ingest_mdir.py

@@ -73,14 +73,11 @@
     tester.start()
 
     pending.put(series)
-
-    # Shut workers down
-    tester.should_die = True
     pending.put(None)
 
-finally:
+except:
     tester.should_die = True
-    pending.put(None)
+finally:
     tester.join()
 
 # Summary hack